University of Groningen
Verb and word order deficits in Swahili-English agrammatic speakers
Abuom, Tom Onyango
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Verb and Word Order Deficits in
Swahili-English Bilingual Agrammatic
Speakers
Tom O. Abuom
.
CLCG
The work reported in this thesis has been carried out under the auspices of
the School of Behavioral and Cognitive Neurosciences (BCN) and the Center
for Language and Cognition Groningen (CLCG). Publication of this thesis was
financially supported by the University of Groningen, the Stichting Afasie Nederland (SAN) and BCN.
Groningen Dissertations in Linguistics 119
ISSN 0928-0030
ISBN 978-90-367-6264-9 (printed version)
ISBN 978-90-367-6265-6 (digital version)
©2013 by Tom O. Abuom
Cover illustration by Ruggero Montalto, www.79s.co
Document layout by Dörte de Kok, prepared with LATEX 2ε , typeset in pdfTEX
Printed by Wöhrmann Print Service, Zutphen, The Netherlands
RIJKSUNIVERSITEIT GRONINGEN
Verb and Word Order Deficits in Swahili-English Bilingual Agrammatic Speakers
Proefschrift
ter verkrijging van het doctoraat in de
Letteren
aan de Rijksuniversiteit Groningen
op gezag van de
Rector Magnificus, dr. E. Sterken,
in het openbaar te verdedigen op
maandag 9 september 2013
om 11.00 uur
door
Tom Onyango Abuom
geboren op 8 juni 1974
te Kisumu, Kenia
Promotor:
Prof. dr. Y.R.M Bastiaanse
Beoordelingscommissie:
Prof. dr. Ria de Bleser
Prof. dr. David Howard
Prof. dr. Loraine Obler
ISBN: 978-90-367-6264-9
Acknowledgments
I express my most sincere gratitude to God for the gift of life and good health
and for having been my guide, light and wisdom throughout the study; and to
all those who have helped me in any way in the course of this study.
“I’ve learned that people will forget what you said, people will forget what you did, but people will never forget how you made them feel.”
-Maya Angelou-. My heartfelt thanks to my supervisor and promoter, Prof.
Dr. Roelien Bastiaanse, for her tireless scholarly and friendly guidance, timely
suggestions and corrections that brought this project to fruition, I owe this
great feeling of accomplishment to her.
My sincere gratitude to Emmah Shah and her team at the Speech and
Language Therapy department as well as the Research Ethics Committee at
the Aga Khan University Hospital (Nairobi, Kenya) for helping me to identify
the participants in this study and granting full access to all the facilities I
needed for this study.
Most sincere thanks to members of the reading committee for my thesis,
Prof. Ria de Bleser, Prof. David Howard and Prof. Loraine Obler for taking
their precious time to read this work.
Special thanks to all members of the neurolinguistics research group of the
University of Groningen, Roelien, Ben, Laurie, Gerard, Roel, Silvia, Dorte,
Olga, Harwintha, Laura, Rimke, Fedor, Joost, Ellie, Seckin and Rui, who have
journeyed with me during the four years of study in Groningen, for their moral
support and immense contribution towards the success of this study through
v
vi
their scholarly presentations, brotherly advice and suggestions. Special thanks
to Dorte and Ruggero for being my paranimfs and for helping me with the
thesis’ layout and designing of the cover. Heartfelt thanks to Trevor and Kelly
for proofreading my thesis.
BCN (Behavioral and Cognitive Neurosciences), CLCG (Center for Language and Cognition Groningen) and SAN (Stichting Afasie Nederland) financially supported the research presented in this thesis, for this I am deeply
grateful to them.
Finally, my heartfelt appreciation to all the members of my family, my
mother Mary, my wife Irene and our two lovely children Reina and Ricky, all my
siblings, relatives and friends who have been a great source of inspiration, moral
support and encouragement throughout my life. I wouldn’t have accomplished
this great work without your love and support.
May God Bless You All!
Groningen, September 9, 2013
Contents
Acknowledgments
v
1 Introduction and thesis outline
1.1 Linguistic accounts of Agrammatism . . . . . . . . . .
1.1.1 Representational deficit accounts . . . . . . . .
1.1.2 The Processing deficit accounts . . . . . . . . .
1.2 The Swahili Language . . . . . . . . . . . . . . . . . .
1.2.1 Characteristics of the Swahili Language . . . .
1.2.2 The Swahili verb complex . . . . . . . . . . . .
1.3 Bilingualism/multilingualism and aphasia . . . . . . .
1.3.1 Bilingual/multilingual aphasia . . . . . . . . .
1.3.2 Agrammatism in bilingual/multilingual aphasia
1.4 Verb and word order deficits in agrammatic aphasia .
1.5 The Research Questions . . . . . . . . . . . . . . . . .
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2 Characteristics of Swahili-English Bilingual Agrammatic
Spontaneous Speech
2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.1.1 Cross-linguistic variations in aphasia symptoms . . .
2.1.2 Bilingual aphasia . . . . . . . . . . . . . . . . . . . .
2.1.3 Syntactic, lexical and morphological deficits . . . . .
2.1.4 Relevant features of Swahili . . . . . . . . . . . . . .
2.1.5 The research questions and expectations . . . . . . .
2.2 Methods and Procedures . . . . . . . . . . . . . . . . . . . .
2.2.1 Participants . . . . . . . . . . . . . . . . . . . . . . .
2.2.2 Materials . . . . . . . . . . . . . . . . . . . . . . . .
2.2.3 Procedures . . . . . . . . . . . . . . . . . . . . . . .
2.2.4 Analysis . . . . . . . . . . . . . . . . . . . . . . . . .
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viii
2.3
2.4
Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.3.1 Comparison of Kenyan and American English samples
2.3.2 Comparison of agrammatic and nbd speakers . . . . .
2.3.3 Verb inflection and time reference through verb forms
Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.4.1 Comparisons with American English data . . . . . . .
2.4.2 Comparison of the English and Swahili samples . . . .
2.4.3 Verb inflection and time reference . . . . . . . . . . .
2.4.4 Linguistic complexity and frequency . . . . . . . . . .
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3 Production and Comprehension of Reference of Time in SwahiliEnglish bilingual agrammatic speakers
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3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
62
3.1.1 Time reference morphology in Swahili . . . . . . . . . .
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3.1.2 Time reference in agrammatic monolinguals . . . . . . .
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3.1.3 Time reference in agrammatic bilinguals . . . . . . . . .
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3.1.4 The current study . . . . . . . . . . . . . . . . . . . . .
69
3.2 Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
70
3.2.1 Participants . . . . . . . . . . . . . . . . . . . . . . . . .
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3.2.2 Materials and procedure . . . . . . . . . . . . . . . . . .
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3.2.3 Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . .
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3.3 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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3.3.1 Overall analysis: . . . . . . . . . . . . . . . . . . . . . .
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3.3.2 Production in English and Swahili . . . . . . . . . . . .
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3.3.3 Comprehension in English and Swahili . . . . . . . . . .
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3.3.4 Individual results on production and
comprehension of English and Swahili past . . . . . . .
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3.3.5 Error types . . . . . . . . . . . . . . . . . . . . . . . . .
80
3.4 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
81
3.4.1 Past time reference in agrammatic speakers . . . . . . .
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3.4.2 Past time reference in English and Swahili . . . . . . . .
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4 Sentence Comprehension in Swahili-English bilingual
agrammatic speakers
4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.1.1 Swahili syntax and verb morphology . . . . . . . . . . .
4.1.2 Theories on sentence comprehension in agrammatic aphasia
4.1.3 Swahili-English bilingual agrammatic aphasia . . . . . .
4.1.4 The predictions for the current study . . . . . . . . . . .
4.2 Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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4.3
4.4
4.2.1 Participants . . . . . . . . . . . .
4.2.2 Materials and procedure . . . . .
Results . . . . . . . . . . . . . . . . . . .
4.3.1 Error analysis . . . . . . . . . . .
4.3.2 Swahili and English compared . .
Discussion . . . . . . . . . . . . . . . . .
4.4.1 The problems with derived order
4.4.2 A working memory deficit? . . .
4.4.3 The effect of morphology . . . .
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5 Sentence Production in Swahili-English bilingual agrammatic
speakers
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5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
5.1.1 Theories of sentence production . . . . . . . . . . . . . . 111
5.1.2 Swahili word order . . . . . . . . . . . . . . . . . . . . . 114
5.1.3 Swahili-English bilingual agrammatic speakers . . . . . 117
5.1.4 The current study . . . . . . . . . . . . . . . . . . . . . 118
5.2 Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
5.2.1 Participants . . . . . . . . . . . . . . . . . . . . . . . . . 119
5.2.2 Materials & Procedure . . . . . . . . . . . . . . . . . . . 119
5.2.3 Scoring . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
5.3 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
5.3.1 Error types . . . . . . . . . . . . . . . . . . . . . . . . . 123
5.3.2 Swahili and English compared . . . . . . . . . . . . . . . 126
5.3.3 Production and comprehension compared . . . . . . . . 126
5.4 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
5.4.1 The DOP-H and linguistic complexity . . . . . . . . . . 127
5.4.2 Production in Swahili and English . . . . . . . . . . . . 129
5.4.3 DOP-H: an overarching processing theory . . . . . . . . 130
6 General Discussion and Conclusion
6.1 Major research findings . . . . . . . . . . . . . . . .
6.1.1 Language dependent variables in spontaneous
6.1.2 Representation vs. processing . . . . . . . . .
6.1.3 Bilingual aphasia and the bilingual brain . .
6.2 The clinical implications of the results of this study .
6.3 Scope for further study/research . . . . . . . . . . .
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Summary
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Nederlandse Samenvatting
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x
Appendices
2.A
2.B
3.A
3.B
3.C
Swahili speech samples . . . . .
English Speech samples . . . .
Accuracy in English production
English verb pairs in the TART
Swahili verb pairs in the TART
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and comprehension
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References
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Grodil
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List of Figures
1.1
1.2
1.3
The syntactic tree according to Hagiwara . . . . . . . . . . . .
The syntactic tree used by Friedmann & Grodzinsky (1997) . .
Map of Swahili language areas . . . . . . . . . . . . . . . . . .
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3.1
3.2
Samples of pictures used for production task . . . . . . . . . . .
A sample of the pictures used for comprehension task . . . . .
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4.1
4.2
Example of pictures in the sentence-picture matching task . . .
Illustration of the interaction effects . . . . . . . . . . . . . . .
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5.1
5.2
Example of pictures in sentence production task . . . . . . . .
Illustration of interaction effects . . . . . . . . . . . . . . . . . .
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List of Tables
1.1
1.2
1.3
1.4
1.5
1.6
A summary of Swahili noun classes (from Ashton, 1982). . .
The information conveyed by the subject agreement marker.
The summary of tense/aspect markers in Swahili. . . . . . .
The six forms of object agreement in Swahili. . . . . . . . .
The Structure of the Swahili verbal root. . . . . . . . . . . .
The six most common types of Swahili verb suffixes . . . .
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2.1
2.2
2.3
2.4
2.5
2.6
2.7
Demographic details and auditory comprehension results . .
Kenyan English and American English agrammatic samples
Comparison of MLU and speech rate . . . . . . . . . . . . .
Comparison of noun and verb production . . . . . . . . . .
Proportions of ungrammatical and embedded sentences . .
Proportion of verb inflections . . . . . . . . . . . . . . . . .
Production of time reference through tense and aspect . . .
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3.1
3.2
3.3
3.4
Demographic details of the agrammatic speakers . . .
Time reference production in Swahili and English . . .
Time reference comprehension in Swahili and English
Distribution of error types in production . . . . . . . .
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4.1
4.2
4.3
4.4
4.5
Demographic details the agrammatic individuals
Examples of target sentences . . . . . . . . . . .
Percentages correct in the Swahili test . . . . . .
Percentages correct in the English test . . . . . .
Error types in Swahili and English . . . . . . . .
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5.1
5.2
Demographic details of the agrammatic participants . . . . . .
Examples of target sentences in the sentence production task .
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5.3
5.4
5.5
5.6
Raw scores on Swahili test .
Raw scores on English test .
Error types on Swahili task
Error types on English task
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CHAPTER
1
Introduction and thesis outline
Aphasia, which literally means ‘not speaking’, is a language disorder caused
by damage to areas of the brain involved in language processing, especially in
the left hemisphere. Its etiologies are varied, but the condition most commonly
results from lesions in the brain which are caused by cerebro-vascular accident
(also known as stroke), intracranial hemorrhage, traumatic injury, tumor or
brain infection. Many aphasic individuals usually have difficulties with both
comprehension and production in all language modalities (listening, speaking,
reading, writing and gesturing), to varying degrees depending on the locus and
the extent of the lesion (Grodzinsky, 1990). The verbal expression at the sentence level of aphasics without global aphasia, where language is totally lost,
is characterized either by errors generally classified as agrammatism (tendency
to use “telegraphic speech” marked by grammatical errors) or by sentence interruptions due to anomias (word finding difficulties).
Currently, a considerable amount of research on aphasia focuses on agrammatism –also known as agrammatic Broca’s aphasia– which is often associated
with a lesion in Broca’s area, the foot of the third convolution of the dominant
hemisphere (Huber, Poeck & Weniger, 2002), though it may also result from
a lesion in other regions in the left hemisphere. Agrammatism, often accom-
1
2
CHAPTER 1. INTRODUCTION
panied by slow, effortful and non-fluent speech, is characterized by a marked
reduction in phrase length and syntactic complexity, but with relatively intact
comprehension abilities. Individual differences in terms of severity ranging from
mild to severe disruptions have been reported (Menn & Obler, 1990; Friedmann,
2005). A classic example of a severe case of agrammatism demonstrated by a
participant in this study is illustrated in (1), the description of the ‘cookie
theft’ (Boston Diagnostic Aphasia Examination, Goodglass & Kaplan, 1972).
Problems with complex constructions such as passive sentences, relative clauses
and other subordinate constructions have also been reported for agrammatic
individuals (Menn & Obler, 1990).
(1)
AGRAMMATIC BROCAS PATIENT E.A.
Examiner: Can you tell me what is happening in this picture?
E.A.: Mum.... first... baby two... boy girl... climbing shelf after... wait wait...
climbing to get cookies... after stool fall... boy fall... forget fall...
Girl hold cookies boy fall. Mum washing... sink.... no no wipe plate....
tap pour sink...tap water flow sink.
Agrammatism has dominated most of the recent linguistic research in aphasia, largely due to the fact that the application of linguistic theories as a tool
for investigation has so far produced promising results. While these linguistic
theories1 have contributed substantially to our understanding of agrammatism, they have focused almost exclusively on monolingual speakers of mainly
1 The
theories and hypotheses are discussed in detail in the following sections of this proposal.
1.1. LINGUISTIC ACCOUNTS OF AGRAMMATISM
3
Indo-European languages. This thesis is unique for two reasons: it provides
further evidence of features of agrammatism from a previously undescribed
language, Swahili, and it also gives an insight into the patterns of manifestation of agrammatism in bilingual individuals speaking two morphologically
different languages (Swahili and English) by testing these linguistic theories
further. The universality of these linguistic theories in relation to Swahili, a
highly agglutinative Bantu language with a complex verb inflection paradigm
(compared to Indo-European languages studied so far), is extensively examined
in this thesis. The findings offer valuable insights into the processing of verb
inflections and word order in the bilingual brain. The thesis also suggests ideas
for effective assessment and rehabilitation of aphasia.
In the next sections the linguistic theories of agrammatism are elaborated, followed by a description of relevant aspects of the Swahili language,
an overview of the relevant studies on multilingualism/bilingualism and aphasia, and a review of the literature on verb and word order deficits in agrammatic
aphasia. The research questions and an overview of the subsequent chapters
conclude this chapter.
1.1
Linguistic accounts of Agrammatism
Attempting to characterize and account for the production and comprehension deficits in agrammatic speakers has been a source of intrigue and controversy among researchers over the years. Several linguistic theories have been
proposed which can be grouped into two main categories: representational
deficit accounts (see Grodzinsky, 1986, 1990, 1995, 2000; Friedmann, 1998,
2002; Friedmann & Grodzinsky, 1997) and processing deficit accounts (see Kolk
1998; Haarmann & Kolk, 1991; Avrutin, 2000; 2006; Bastiaanse & Van Zonneveld, 2006; Bastiaanse, Koekkoek & Van Zonneveld, 2003; Thompson, 2003).
However, whether agrammatism can be characterized fully as either a representational deficit or a processing deficit is still a matter of debate. Within the
two main categories, there are a number of theories aiming to explain either
production and/or comprehension deficits. The following sections present the
two categories of linguistic accounts, focusing on the most influential theories
of agrammatism, some of which are tested extensively in this study.
4
CHAPTER 1. INTRODUCTION
1.1.1
Representational deficit accounts
Proponents of the representational deficit accounts assume that the speech production and comprehension difficulties generally experienced by agrammatic
speakers reflect a partial loss of syntactic competence due to incomplete linguistic representation. Lukatela et al. (1995) used the term ‘structural deficit
hypothesis’ to explain the same phenomenon, arguing that agrammatism reflects impairment in the knowledge of grammar, rather than a lack of processing
abilities. According to these proponents, the grammatical representations of a
language are assumed to be lost in agrammatism, and are therefore unavailable
to the patients. By mainly focusing on the syntactic tree, they argue that parts
of the sentence representation, such as CP-nodes or traces, are missing; hence
the patients cannot use them. Such patients, for instance, will not be able to
form wh-questions nor comprehend sentences in which elements are not in their
base positions. We focus on two main theories of the representational deficit
accounts: the Tree Pruning Hypothesis (Friedmann & Grodzinsky, 1997) and
the Trace Deletion Hypothesis (Grodzinsky, 1984; 1995).
The Tree Pruning Hypothesis
Friedmann and Grodzinsky (1997) proposed the Tree Pruning Hypothesis based
on the initial assumption of Ouhalla (1990) and Hagiwara (1995)2 that the functional categories at the top of the syntactic tree are unavailable to agrammatic
speakers. Ouhalla (1990) assumed that agrammatic speakers cannot project
above the Verb Phrase (VP); any node above the VP is missing in the syntactic
tree. Therefore, the agrammatic individual speaks in ellipses in which free and
bound morphemes are missing. Hagiwara (1995) propounded Ouhalla’s idea
by proposing that functional heads and their projections in lower positions of
the sentence structure are more accessible than those in higher positions for
agrammatic speakers. She assumes that the Complementizer Phrase (CP) is
unavailable (see Figure 1.1).
Hagiwara’s assumption that only the CP is missing was based on data from
Japanese agrammatic speakers as well as previously reported data from agrammatic speakers of Romance and Germanic languages. The TPH, meanwhile,
includes the Tense Phrase (TP) in the missing part of the syntactic tree, based
on Pollock’s (1989) theory that the IP node is split into separate Tense and
2 Note
that Hagiwara, however, assumes a processing deficit: a deficiency in resources to
contruct a full syntactic tree.
1.1. LINGUISTIC ACCOUNTS OF AGRAMMATISM
5
CP
C'
Whquestions
IP
Complementizer
I'
AgrOP
Tense & Agreement
AgrO'
VP
Object
Agreement
V
Figure 1.1: The syntactic tree according to Hagiwara, from which the CP might be missing
in agrammatic sentence representation.
CP
C'
Whquestions
TP
Complementizer
T'
AgrP
Tense
Agr'
VP
Agreement
V
Figure 1.2: The syntactic tree used by Friedmann & Grodzinsky (1997), based on Pollock’s
theory that the IP node is split into separate Tense and Agreement nodes.
Agreement nodes (TP and AgrP). Friedmann and Grodzinsky (1997) assumed
the TP is above the AgrP in the syntactic tree3 following Pollock’s (1989)
3 Tense
Phrase is considered to be located above Agreement Phrase in the phrase structure
(syntactic tree) of Hebrew. However, there are several languages in which TP is below
AgrP, such as Dutch and German.
6
CHAPTER 1. INTRODUCTION
theory, as reflected in Figure 1.2. The TPH predicts that the syntactic trees
underlying agrammatic phrase structure are pruned from the Tense node up,
including the CP. This implies that the Agreement node and all the nodes
below it remain unavailable to the agrammatic speaker.
Friedmann & Grodzinsky (1997) reported the case of an agrammatic speaker
of Hebrew who showed intact agreement inflection, but impaired tense inflection, use of copulas, and embedded clauses. Subsequently, Friedmann (2000)
examined the performance of 16 agrammatic speakers4 on tests of wh-question
and yes/no question formation and found that higher nodes of the syntactic
tree, necessary for wh-questions in English, Arabic and Hebrew, as well as for
yes/no questions in English, are impaired. Generalizing, the author concluded
that the agrammatic speakers had intact Agreement, but were impaired at the
levels of Tense and Complementizer due to the syntactic tree being “pruned”
between the Tense Phrase and the Agreement Phrase.
The TPH, thus, proposes that agrammatic speakers can successfully produce agreement inflection, but they will have difficulties producing objectextracted sentences, complementizers or tense inflections in English and Hebrew. This hypothesis has been challenged by a number of studies. Lee, Milman and Thompson (2008) and Penke (2001) have found Tense, but not Complementizers, impaired; Bastiaanse (2008) and Lee et al. (2008) have found
both Tense and Agreement impaired; whereas Burchert, Swoboda-Moll and
De Bleser (2005) found selective impairments of both Tense and Agreement in
agrammatic speakers. Also, the TPH suggests that all the syntactic representations under TP are intact, which, however, is not the case as demonstrated by
other studies (Bastiaanse et al., 2003; Burchert, Meissner & De Bleser, 2008).
While the Tree Pruning Hypothesis has mainly focused on production problems, the Trace Deletion Hypothesis has been introduced to explain comprehension problems in agrammatic speakers under representational deficit accounts.
Trace Deletion Hypothesis
The Trace Deletion Hypothesis (TDH) was proposed by Grodzinsky (1984) to
account for comprehension deficits in agrammatic speakers. It has undergone
a series of revisions over the years (Grodzinsky, 1986; 1995; Drai & Grodzinsky, 2006). The TDH basically assumes that all argument traces are missing
from the sentence representations of agrammatic speakers. Traces are abstract
4 There
were 13 Hebrew speakers, 2 Arabic speakers, and 1 English speaker.
1.1. LINGUISTIC ACCOUNTS OF AGRAMMATISM
7
markers left by moved constituents in their original D-structure; they ensure the
correct interpretation of thematic information. In sentences, verbs assign thematic roles to arguments in their original positions. Moved arguments receive
their thematic roles through traces connecting them to their original positions.
According to the TDH, agrammatic speakers have great difficulty understanding grammatically complex sentences such as passives, object clefts and object
relatives, because elements in such sentences have moved from their original
positions. Grodzinsky argues that the traces linking the moved constituents to
their original positions are missing from the sentence representations of agrammatic individuals, hence thematic roles cannot be assigned to the moved elements. This is illustrated in (2), where the indexations ‘i’ indicate the relation
between the moved constituent and its orginal position.
(2)
(a) The girl pushed the boy.
(b) The boyi was pushed i by the girl.
(c) The girli who i is chasing the boy is tall.
(d) It is the girli who i is chasing the boy.
In a passive sentence such as (2b), the NP (‘the boy’) has been moved from
its original position to the first position in the sentence, but it does not function as the agent. It is assigned a correct thematic role by being co-indexed
to its trace at the original position. Agrammatic speakers have been found
to have difficulties in correctly interpreting the NP (‘the boy’) as the patient
of the pushing event. Grodzinsky argued that when agrammatic speakers encounter such difficulties, they may resort to non-syntactic ways of interpreting
the sentence, that is, a default or linear strategy, which assigns an agent role
to the first NP in the sentence. However, they can simultaneously interpret
the second NP (‘the girl’) as the agent because its thematic role is assigned by
the “by-phrase”. As a result, they are faced with a representation consisting
of two agents (‘the boy’ and ‘the girl’), leading to guessing, as shown by scores
at chance level on binary choice tests. The default strategy has also been suggested to explain the above chance level performance of agrammatic speakers
in sentences such as subject relatives (2c) and subject-clefts (2d). These sentences contain traces as well, but the default strategy (the first NP is the agent)
results in the correct interpretation.
The TDH and the default strategy proposed by Grodzinsky, however,
cannot account for all comprehension deficits in agrammatic speakers. Fur-
8
CHAPTER 1. INTRODUCTION
thermore, several researchers have disputed the TDH. For example, Berndt,
Mitchum and Haendiges (1996), after a meta-analysis of a series of studies on
the comprehension of passive and active constructions, claimed that there is no
homogeneous pattern of comprehension errors in agrammatic speakers. Beretta
and Munn (1998) showed that agrammatic representations do not involve double agent representations in passive sentences, as suggested by Grodzinsky’s
default strategy. Pinango (2000) suggested that agrammatic individuals can
represent subject-NP-traces as shown by their excellent performance on comprehension of unaccusative sentences. The recent revised version of the TDH
by Drai and Grodzinsky (2006), which includes data from Dutch and German
agrammatic speakers, has also been disputed by Bastiaanse and Van Zonneveld
(2006) through their Derived Order Problem-Hypothesis (DOP-H), which is
a processing account. Unlike the TDH which is restricted to comprehension
deficits, the DOP-H is an overarching theory that includes both comprehension
and production deficits in agrammatic speakers. We discuss the DOP-H in the
next section under the processing deficit accounts.
1.1.2
The Processing deficit accounts
Proponents of the processing deficit accounts claim that the linguistic competence of agrammatic individuals is unaffected by their lesions, and that
the observable difficulties are instead the result of reduced capacities that are
needed for computing complex linguistic operations. Simply put, they argue
that agrammatic speakers have their linguistic representations intact, but that
they have limited computational resources to exploit them fully (Avrutin, 2000;
2006; Burchert, Swoboda-Moll & De Bleser, 2005; Bastiaanse & Van Zonneveld,
2005; Thompson, 2003). They dispute the proponents of representational accounts’ suggestion that agrammatism is “an all or nothing” phenomenon, based
on the variability in agrammatic speakers behaviour. The processing deficit
accounts predict that agrammatic speakers will show variation in their use of
particular functional elements based on the complexity of the clause. We focus on four theories of processing accounts that are relevant to our project:
the Derived Order Problem-Hypothesis (Bastiaanse & Van Zonneveld, 2005),
the Tense Underspecification Hypothesis (Wenzlaff & Clahsen 2004, 2005), the
Tense and Agreement Underspecification Hypothesis (Buchert et al., 2005) and
the Past Discourse Linked Hypothesis (Bastiaanse, Bamyaci, Hsu, Lee, Yarbay
Duman & Thompson, 2011).
1.1. LINGUISTIC ACCOUNTS OF AGRAMMATISM
9
The Derived Order Problem-Hypothesis
The Derived Order Problem-Hypothesis (DOP-H) was formulated by Bastiaanse and Van Zonneveld (2005) based on data from Dutch and English agrammatic speakers. According to the DOP-H, all languages have a base order in
which constituents that naturally belong together are adjacent in their representations. The base word order is not the same for all languages: English, for
example, has a base word order of Subject-Verb-Object (SVO), whereas both
Dutch and German have Subject-Object-Verb (SOV) as a base order. However,
other word orders – known as ‘derived orders’– in which the constituents have
overtly moved from their base positions are also possible. The DOP-H proposes
that agrammatic speakers will have difficulty comprehending and producing all
sentences with derived orders, but that sentences in base order are relatively
spared.
Several studies have supported this hypothesis. For Dutch, Bastiaanse et
al., (2002a) reported that agrammatic speakers showed greater difficulty with
finite verb production in the matrix clause (derived order) than in embedded
clauses (base order). For English, Bastiaanse and Thompson (2003) reported
that agrammatic speakers had more problems with auxiliaries in derived position in yes/no questions than with auxiliaries in base position in declarative
sentences. Recently, two studies were performed on the production of sentences with scrambled objects. Burchert et al. (2008) and Yarbay Duman et
al. (2008) have reported that agrammatic speakers have more difficulties producing sentences with object scrambling than sentences with objects in their
base positions in German and Turkish, respectively.
Bastiaanse and colleagues (2002a) concluded that agrammatic speakers are
better at producing and comprehending sentences in which the constituents
are in base order than sentences with derived orders, and that movement of
constituents low in the syntactic tree is impaired as well, contrary to the predictions of the TPH. The DOP-H can only account for and is only meant to
describe word order problems. It cannot account for all agrammatic phenomena, such as the specific difficulties with verb inflection that have been reported
in several languages (see: Wenzlaff & Clahsen, 2004; 2005, for German; Friedmann & Grodzinsky, 1997, for Hebrew; Stavrakaki & Kouvava, 2003, for Greek;
Yarbay Duman & Bastiaanse, 2009, for Turkish).
10
CHAPTER 1. INTRODUCTION
The Tense Underspecification Hypothesis
Wenzlaff and Clahsen (2004, 2005) proposed the Tense Underspecification Hypothesis (TUH) after analysis of data from German agrammatic speakers. In
this account, the authors argue that the difficulties with tense evident in the
performance of German agrammatic speakers are the result of the tense features being underspecified. In their first study (Wenzlaff & Clahsen, 2004),
both tense and agreement were examined through multiple choice and grammaticality judgment tasks. They found both past and present tense to be more
impaired than agreement. Grammatical mood, which was tested in their subsequent study (Wenzlaff & Clahsen, 2005), was found to be relatively intact
in agrammatic speakers. Wenzlaff and Clahsen, therefore assume that tense
features are underspecified in agrammatic aphasia, resulting in difficulties with
expressing reference to the past, present and future. They argue that it is not
the syntactic category of tense per se nor its position in the syntactic tree that
is responsible for the difficulties of agrammatic speakers, but the interpretability of the features of tense used for time reference. The tense features express
an extrasentential relationship between verb inflection and a timeframe outside
the sentence, while agreement features express an intrasentential relationship
between the subject and the finite verb. The TUH, therefore, predicts intact
agreement features and underspecified tense features in agrammatic speakers’
production and comprehension. This theory was disputed by Burchert et al.
(2005), who proposed a slight adaptation: the Tense and Agreement Underspecification Hypothesis.
The Tense and Agreement Underspecification Hypothesis
The Tense and Agreement Underspecification Hypothesis (TAUH), formulated
by Burchert et al. (2005), assumes that tense and agreement can be affected
independently in agrammatic speakers. The authors examined both tense and
agreement in German agrammatic speakers, applying a similar test design as
used by Wenzlaff & Clahsen (2004; 2005). Their findings revealed a bidirectional individual variation: some agrammatic speakers had problems with
tense, whereas others had problems with agreement. Burchert et al. (2005),
therefore, argued that a selective underspecification of tense or agreement leads
to impaired tense or agreement morphology, whereas a concurrent underspecification of both tense and agreement results in problems with both tense and
agreement morphology in agrammatic production. The assumption of the
1.1. LINGUISTIC ACCOUNTS OF AGRAMMATISM
11
TAUH, that both tense and agreement can be impaired independently has
been confirmed in other studies, such as Bastiaanse (2008). Bastiaanse has
argued that agreement may not be intact or better preserved than tense in
every language if the current cross-linguistic data are considered; however, she
attributes the tense problems to time reference rather than to its position in
the syntactic tree. Bastiaanse (2008) argues that it is not a ‘tense problem’ per
se, but a problem of time reference. Reference to the past is especially difficult
for agrammatic speakers because untensed forms referring to the past, such as
participles, are impaired as well. The time reference problem is accounted for
by the Past Discourse Linked Hypothessis (PADILIH; Bastiaanse et al., 2011).
The Past Discourse Linked Hypothesis
Avrutin (2000; 2006) introduced the idea of two levels of syntactic processing
into aphasiology: the “narrow syntax” processing which takes place within the
sentence level, and the “discourse syntax” processing needed for interpretation
of elements that need extrasentential information in order to be interpreted.
Discourse linked elements have to be processed by discourse syntax, which, according to Avrutin (2006), is impaired in agrammatic aphasia since the extra
processing resources required for discourse linking (‘discourse syntax’ but not
‘narrow syntax’) are not sufficiently available for agrammatic speakers due to
their brain damage. Avrutin (2000; 2006), therefore, argues that the general
difficulty with tense for agrammatic speakers arises from the fact that the processing of tense requires discourse linking. Zagona (2003; in press), however,
argues that only past tense requires discourse linking, whereas both present
and future tenses do not. She explains that since speech time and event time
do not coincide when referring to a past event, a discourse-linked relation has
to be established between the speech time and an earlier event. For reference
to non-past events (present and future), such linking is not needed. Bastiaanse
and colleagues (2011) adapted Zagona’s theory and extended discourse linking
to include not only past tense, but reference to the past through grammatical morphology in general. The proposed Past Discourse Linked Hypothesis
(PADILIH) predicts that time reference to the past is difficult for agrammatic
speakers because it is discourse-linked, whereas time reference to both the
present and the future are not.
The PADILIH was proposed by Bastiaanse and colleagues (2011) after considering the results of several cross linguistic studies showing impaired time
reference to the past for agrammatic speakers (Stavrakaki & Kouvava, 2003;
12
CHAPTER 1. INTRODUCTION
Nanousi, Masterson, Druks & Atkinson, 2006; Bastiaanse, 2008; Yarbay Duman & Bastiaanse, 2009; Bastiaanse et al., 2011). Stavrakaki and Kouvava
(2003) analyzed the production of tense, aspect and agreement in the spontaneous speech of two Greek agrammatic speakers and found impaired production of past tense compared to the present tense, and past tense with perfective
aspect was more impaired than past tense with imperfective aspect; subjectverb agreement was realtively spared. Nanousi et al. (2006) reported similar results in their study of Greek agrammatic speakers who showed impaired
production of perfective aspect. The pattern was replicated in the performance of Dutch agrammatic speakers on a sentence completion task reported
by Bastiaanse (2008): participants made more errors with past tense than
with present tense and with past participles than with infinitives. Yarbay
Duman and Bastiaanse (2009) found the same for past tense/perfect aspect
versus future tense/imperfect aspect in Turkish agrammatic speakers. These
findings were further confirmed by the results of a cross-linguistic study by
Bastiaanse and colleagues (2011) in which the Test for Assessing Reference of
Time (TART; Bastiaanse et al., 2008) was used to test both the production and
comprehension of time reference to the past, present and future among agrammatic speakers of Chinese, English and Turkish. While both the production
and comprehension of reference to the past time frame through verb inflection
was selectively impaired among Turkish and English agrammatic speakers, the
Chinese agrammatic speakers showed a similar pattern only on comprehension.
The Chinese agrammatic speakers’ production of all three time frames (past,
present and future) was equally affected, which the authors attribute to a general problem with aspectual adverbs (see Bastiaanse, 2013). In Chinese, time
reference is expressed through aspectual adverbs rather than verb inflections as
in other languages. This theory has been tested extensively in both languages
of this study’s bilingual agrammatic speakers in Chapter 3.
1.2
The Swahili Language
The Swahili language, also known as Kiswahili, is one of the most widely spoken languages in Africa. It belongs to the large family of Bantu languages
spoken in the southern half of the African continent. It is spoken as a first
language by approximately five million people who live on the east coast of
Africa that stretches from the south of Somalia to the north of Mozambique,
1.2. THE SWAHILI LANGUAGE
13
including the islands of Pate, Lamu, Pemba, Zanzibar and Mafia. From east to
west, the area of influence of Swahili extends from Tanzania and Kenya through
the interior of Congo (ex-Zare), up to Uganda, Burundi, Zambia and Malawi
(see Figure 1.3). Approximately two centuries ago, Swahili, which means “the
coast”, became the language of contact and communication between the people
who came from elsewhere (e.g., explorers, merchants, slave traders, colonizers,
missionaries, etc.) and the populations of the coast and the interior of the
continent. Developing as a lingua franca, it preserved its Bantu grammatical
structure characterized by a system of nominal classes and agglutinative verbal
constructions, while it was lexified by a substantial number of foreign words, for
the greater part from Arabic and Persian, but also some Portuguese, German
and, most recently, English. Perrot (1969) points out that Swahili has incorporated words from many other sources and “Bantuized” them to such an extent
that most speakers do not recognize that they are foreign words. However, the
structure of the Swahili language remains Bantu, notwithstanding the large
number of borrowed foreign words. It was first written in Arabic characters
and, more recently, in the Roman alphabet.
Figure 1.3: A section of the Map of Africa showing countries in which the Swahili language
is spoken (from Stanford.edu.)
In the following sections, some of the general characteristics of the Swahili
language and its verbal system, which are crucial to this project, are explored.
14
CHAPTER 1. INTRODUCTION
1.2.1
Characteristics of the Swahili Language
The word order of Swahili, like that of English, is Subject-Verb-Object (SVO).
It is an agglutinative language, with considerable prefixing and suffixing. Like
other Bantu languages, Swahili has a derivational system, by which derivational affixes can be attached to the original stem in order to express an agent,
“state” of a thing and totality. Derivation in Swahili takes place at nominal
and verbal levels. At the nominal level, as illustrated in Mohammed (2001),
a word like ongoz-a (‘lead’) can become u-ongoz-i (‘leadership’), ki-ongozi (‘leader’), ma-ongoz-i (‘direction’) and mw-ongoz-o (‘guideline’). At the
verbal level, derivation subsumes six major grammatical categories: passive,
stative, causative, applicative, conversive and reciprocal.
Unlike derivational systems which cause a change of word class, Swahili
has an inflectional system whereby the grammatical class of a word does not
change with the addition of inflectional affixes. The inflectional system operates
largely at three levels: nominal, pronominal5 and verbal. Inflectional affixes
are normally attached to a word stem to signal grammatical relationships such
as number and possession. At the nominal level, a class-prefix is attached to
the nominal stem (see Table 1.1). For instance, the noun stem, toto (‘child’)
becomes m-toto (‘one child’) and wa-toto (‘children’). At the verbal level,
inflectional affixes are added to the verbal stem which normally comprises the
root, with or without other suffixes and the final particle -a. For instance, the
word chez-a (‘play’) can become a-na-chez-a (‘s/he is playing’) or wa-na-cheza (‘they are playing’), expressing person, number and tense. Moreover, the
verbal system can be very agglutinative in nature, and in most cases can be
regarded as a complete sentence consisting of the subject, verb and the object
as shown in (3). Ni is the subject prefix indicating the first person singular;
the particle na is the tense marker for present; wa is the pronoun functioning
as a direct object, the third person plural; and heshimu ‘respect’ is the verb
stem. U is a mandatory final suffix. The verb root heshim itself does not
change, and can only be meaningful after acquiring the relevant affixes.
(3)
Ni-na-wa-heshimu
sana
I-PRESENT-them-respect a lot
‘I respect them a lot.’
5 The
nominal and pronominal levels are not the focus of this study; therefore, they will
not be discussed further.
1.2. THE SWAHILI LANGUAGE
15
Table 1.1: A summary of Swahili noun classes (from Ashton, 1982).
Noun class
1.
2.
3.
4.
5.
6.
7.
8.
M-WA
M-MI
JI-MA
KI-VI
N-N
U-U
KU
PA
Example
Singular
Plural
Mtu (‘a person’)
Watu (‘persons’)
Mlango (‘door’)
Milango (‘doors’)
Jiwe (‘stone’)
Mawe (‘stones’)
Kijana (‘a boy’)
Vijana (‘boys’)
Ndugu (‘brother’)
Ndugu (‘brothers’)
Ukuta (‘wall’)
Kuta (‘walls’)
Kusoma (‘reading’) Kusoma (‘reading’)
— this class inherently contains one noun only (mahali / ‘place’),
signifying location
The Swahili language is also characterized by concordial agreement. The
noun or pronoun governs the agreement of all the other words that are syntactically associated with it. Such agreement, according Mohamed (2001), is
signaled by concordial prefixes and points to person, gender and number. (4) is
an illustration of how the concept of agreement operates in Swahili. The concordial prefixes are underlined, and it is clear that they agree with the nouns.
Traditionally, Swahili has eight noun classes (Loogman, 1965 & Ashton, 1982)
and each concordial prefix is determined by its noun class. Table 1.1 gives
a summary of the Swahili noun classes, a traditional classification of Swahili
nouns according to their initial prefix (Ashton, 1982).
(4)
mrefu ule u-me-anguka
leo.
Mti
A tree tall
that it-PERFECT-fall today
‘That tall tree has fallen down today.’
The verbal morphology system is discussed in detail in the following sections.
1.2.2
The Swahili verb complex
The distinguishing feature of the Swahili verb is its agglutinative form. Depending on the context, a certain number of prefixes and suffixes must be attached
to the verb root for it to be functional. These affixes usually assume distinct
16
CHAPTER 1. INTRODUCTION
positions and functions. The verb root cannot be further reduced morphologically. When a final suffix -a is attached to the verb root, it becomes a verb
stem. With an exception of a few verbs borrowed from Arabic, all verb stems
in Swahili end in -a. Illustrated below is the order of affixed and root elements
in the verbal complex (5) and an example (6). The subject agreement, tense,
root and the final vowel are obligatory in every affirmative Swahili utterance
(Ashton, 1982).
(5)
Subject Agreement
+
Tense
SA
(6)
+
Object Agreement
T
+
Root
OA
R
+
Suffixes
+
Final Suffix
FS
Alimpiga
‘S/he hit him/her’
A
SA
+
+
li
T
+
+
m
OA
+
+
pig
R
+
+
a
FS
The structure, occurrence and function of each of these elements are described in order in the following sections.
Subject Agreement
The subject agreement marker occurs in the initial position of the verb complex.
It relates to the noun being the subject of the verb in the sentence and it
is obligatory in almost all contexts in Swahili, whether the subject is overtly
realized or not. It conveys almost all the information about the noun, including
the class, the number and the person; therefore, it can also function as the
pronoun in instances where the subject noun is not realized as shown in (6).
The subject agreement markers vary depending on the class, person, number
and role of the subject noun. See Table 1.2.
The personal pronouns in the sentences in Table 1.2 are optional and are
generally omitted since the subject agreement markers serve the same functions;
however, they can be included for emphasis. Ashton (1982) and Myachina
(1981) argue that the subject agreement markers are indispensable components
of the verbal complex. Krifka (1995), in his survey of Swahili syntax, added
that subject agreement is obligatory in all cases with the exception of certain
verb tenses such as the habitual ‘hu’ (eg. Mimi huanguka: ‘I usually fall’).
1.2. THE SWAHILI LANGUAGE
17
Table 1.2: The information conveyed by the subject agreement marker.
Optional Pronoun
st
1 Singular
2nd Singular
3rd Singular
1st Plural
2nd Plural
3rd Plural
Mimi
Wewe
Yeye
Sisi
Ninyi
Hawa
SA
T
Root
FS
subject
past
(to fall)
final
niuatumuWa-
-li-li-li-li-li-li-
-anguk-anguk-anguk-anguk-anguk-anguk-
-a
-a
-a
-a
-a
-a
‘I fell’
‘You fell’
‘He fell’
‘We fell’
‘You (all) fell’
‘They fell’
Tense/Aspect
The Swahili tense/aspect marker is obligatory in every indicative utterance. It
is ungrammatical to omit the tense/aspect marker whether or not the temporal
reference is clear from the discourse or other sources. A summary of various
tense /aspect markers occurring in Swahili are presented in Table 1.3 below.
Table 1.3: The summary of tense/aspect markers in Swahili.
Tense/Aspect
morpheme
Meaning
-li-na-/-ahu-ta-ka-me-sha-ki-nga-ku-
past
present, on-going
habitual
future
narrative, resultative
present perfect
present perfect completive
conditional
hypothetical
infinitival
The -li- morpheme is used as a simple past tense marker to refer to a past
activity without reference to a specific time. According to Comrie (1976),
the -li- morpheme is an absolute tense, and it can be used as an anchoring
tense in discourse independent of the surrounding context. The -na- and a- morphemes are mutually interchangeable according to Mohammed (2001),
18
CHAPTER 1. INTRODUCTION
and both can be used to refer to actions taking place at the present moment.
The -a- tense is considered merely as a dialectical variant of the -na- tense
marker; however, the -a- is sometimes used to state facts regardless of a time
dimension or to state scientific truths that are not necessarily connected to the
present (Ashton, 1982). Also related to the present is the hu- prefix for the
habitual present tense. The hu- tense marker is used to speak about habitual
or recurrent actions without making reference to any specific time. It does not
take subject prefixes/agreement. -Ta- is a future tense marker that describes
events assumed to follow the present time. It is regarded as a relative tense
marker that takes its reference from the immediately preceding context or the
matrix tense when in an embedded clause. The morphemes: -ka-, -me-, and
-sha- are also considered as relative tense markers. The -ka- tense marker
is generally associated with the notion of consecutiveness. Steere (1976) and
Ashton (1982) point out that the -ka- tense is used to express an action or
state which follows another action, and it is most frequently used in narratives
and story-telling in order to drive the story line forward in time. It is also
referred to as a continuative marker that takes anaphoric interpretation from
the previous action (see example (7)).
(7)
A-li-ruka
chini a-ka-kimbia
S/he-PAST-jumb down s/he-CONSEC-run
‘He jumped down, he (then) ran off.’
Both the -me- and -sha- are present perfect tense markers. They both refer
to a past activity which has relevance to the present time, however, the difference is that -sha- carries a more emphatic sense of completion. The English
translations of -me- is “have done X”, whereas -sha- is “have already done X”.
The subsequent tense morphemes -nga- and -ki- are less commonly used in
Swahili. The -nga- is a hypothetical morpheme, and is by far the least used of
all the tense affixes. The -ki- is a habitual or conditional marker comparable
to ‘if’ and “when” in English. Finally, the -ku- is an infinitive marker that
serves two functions. It functions as the verbal infinitive which corresponds to
the English infinitive usually signaled by use of ‘to’ before the verb. It also
functions as a verbal noun or gerund. See examples (8) and (9).
(8)
A-na-penda
ku-cheza
S/he-PRESENT-like to-play
‘S/he likes to play’
1.2. THE SWAHILI LANGUAGE
(9)
19
Ku-cheza sana
ha-kufai
To-play
excessively not-good
‘Playing excessively is no good’
Some of the tense morphemes mentioned here are significant in this study.
The three tense prefixes: -li- (for past), -na- (for present) and -ta- (for future)
are the most commonly used for the reference of time, and will therefore be
discussed further in our discussion of the time reference of agrammatic speakers
of Swahili.
The Object Agreement
The next component of the verb complex is the object agreement. The object
agreement marker must agree with the person and noun class of the object
in the sentence. According to Ngonyani (1996), object agreement in Swahili,
like in other Bantu languages, is obligatory in simple transitive sentences when
the object is specific and/or animate. However, in situations where the object
of the sentence is inanimate and not specific, the object agreement marker is
optional. See examples (10) for an animate and specific object and in (11) for
an inanimate and non-specific object, according to Keach (1995). There are six
forms of personal pronoun object agreement as shown in Table 1.4. However,
there is an additional reflexive object -ji- used when the subject and the object
are the same person in a sentence, as shown in (12).
(10)
(a)
Ni-na-m-penda
Juma
I-PRESENT-him/her-like Juma
‘I like Juma’
(b)
*Ni-na-penda Juma
(11)
(a)
Ni-na-ki-soma
kitabu
I-PRESENT-it-read a book
‘I am reading the book’
(b)
Ni-na-soma
kitabu
I-PRESENT-read a book
‘I am reading a book’
20
CHAPTER 1. INTRODUCTION
(12) A-na-ji-penda
S/he-PRESENT-him/herself-like
‘S/he loves him/herself.’
Table 1.4: The six forms of object agreement in Swahili.
Object agreement
-ni-ku-m-tu-mu-wa-ji-
person
1st singular
2nd singular
3rd singular
1st plural
2nd plural
3rd plural
Reflexive
It is important to note that a verb can be subcategorised for only one object. In situations where a sentence has both a direct (accusative) and indirect
(dative) object, the indirect object is included in the verb complex, whereas the
direct object is either stated in the sentence as a noun, or possibly understood
by the context. See the example (13) below.
(13) Wa-me-m-pa
[mtoto] vitabu
They-PERFECT-him/her-give [child] books
‘They gave [the child] some books’
The Verbal Root
The Swahili verbal root is the core of the verbal paradigm. Similar to most
Bantu languages, the verbal root is generally monosyllabic, with the exception
of some verbs originally borrowed from other languages, particularly Arabic.
The structure of the verbal root is predominantly CVC, but other structures
are also possible as illustrated in Table 1.5. An obligatory final suffix is usually
attached to the verbal root to form a verb stem. Optionally, one or more
suffixes are attached to the verbal root to give varying shades of meaning to
the verb, for example, passive, stative, causative, reciprocal, and prepositional,
among others.
Swahili has very few monosyllabic verbs whose roots contain a single consonant – although they happen to be the most commonly used verbs in the
1.2. THE SWAHILI LANGUAGE
21
Table 1.5: The Structure of the Swahili verbal root.
Root structure
Example + final suffix (verb stem)
English Translation
C
VC
CVC
CVCC
VCVC
VCC
VCCVC
p-a
iv-a
pig-a
shind-a
azim-a
amb-a
anguk-a
‘give’
‘become ripe, mature’
‘hit’
‘win’
‘borrow’
‘adhere’
‘fall’
language. To be functional in a sentence, the syllable ‘ku’ must be inserted
before these monosyllabic verb roots to make them disyllabic, since the stress
in Swahili falls on the final syllable where a prefix cannot carry stress as in (14).
However, in cases where certain prefixes that carry stress (such as ‘haku’) occur
with the verb root, the ‘ku’ is not inserted as in (15).
(14) A-me-ni-kup-a
chai
S/he-PERFECT-me-give-FINAL SUFFIX tea
‘S/he gave me some tea’
(15) Haku-ni-p-a
chai
Not-me-give-FINAL SUFFIX tea
‘(S/he) did not give me some tea.’
The Suffixes
Swahili verbs may have up to three optional suffixes attached to the verbal
root in addition to (and preceeding) the final suffix. The Swahili verbal root
is considered rich enough to allow various forms of conjugations through suffixations such that numerous meanings are produced with subtle differences
(Mohammed, 2001). The six most common types of Swahili verb suffixes
are classified according to their functions: passive, stative, causative, applicative/prepositional, conversive and reciprocal, as illustrated in Table 1.6.
For this study, the passive form, which is common in Swahili, will be discussed in detail in chapters 4 and 5. The passive in Swahili resembles that of
22
CHAPTER 1. INTRODUCTION
Table 1.6: The six most common types of Swahili verb suffixes and their functions.
Suffix Function
Description
Examples
Passive
Causative
Causes the theme to be
subject of the sentence
Makes the verb causative
Applicative/
prepositional
Reciprocal
Introduces an additional
argument to the sentence
Reciprocalizes the verb
Stative
Makes the verb stative
Conversive
Reverses the meaning of
the verb
chez-a (play) → chez-w-a (be
played)
chez-a (play) → chez-esh-a
(cause to play)
chez-a (play) → chez-e-a (play
for)
chez-a (play) →chez-ean-a
(play with each other)
chez-a (play) → chez-ek-a
(played)
pang -a (arrange) → pang -u-a
(disarrange)
other languages in that the subject of the sentence is the theme/patient of the
action. The passive morpheme -w- is part of the verb as in the example below
(16). The theme becomes the grammatical subject, whereas the logical subject
appears optionally in the na (by) phrase at the end of a sentence.
(16)
(a)
A-li-ni-piga
ACTIVE
s/he-PAST-me-hit
‘S/he hit me’
(b)
Ni-li-pig-wa
(na yeye)
PASSIVE
I-PAST-hit-PASSIVE (by him/her)
‘I was hit (by him/her)’
The Final Suffix
The final suffix, also known as the verb-ending suffix, is an obligatory component of the Swahili verb paradigm. The final suffix has generally been described
as a mood vowel in Swahili and other Bantu languages. There are three distinct forms of the final suffix in most Bantu languages, including Swahili: [a], [e]
1.3. BILINGUALISM/MULTILINGUALISM AND APHASIA
23
and [i]. In Swahili, this morphological distinction is associated with the corresponding semantic distinctions: the -a is associated with indicative/imperative
mood, the -e- is associated with subjective mood, and the -i- associated with
negation (Bresnan & Mchombo, 1987). Most Swahili verb stems (verbal root
+ final suffix), with the exception of loan verbs, are in indicative/imperative
mood. The Swahili imperative verb form could function as either a simple
command or an appeal directed to the second person singular wewe (you) or
plural ninyi (both/all of you). When addressed to one person, the verb stem
alone forms the imperative; however, when more than one person is addressed,
a pluralizing suffix -ni- is added to the verb stem and the final -a- changes to
-e- as shown in example (17).
(17) Kula!
(‘eat!’) SINGULAR
Kule-ni (‘eat!’) PLURAL
The Swahili subjunctive verb form may express a wish, desire, request,
suggestion, obligation, purpose or intention. It usually consists of the subject
prefix, the verbal root and the final vowel -e-(e.g. Ni-saidi-e! (‘help me!’) or
A-end-e! (‘let him go!’). The negation final vowel -i expresses negation with no
particular reference to time (Mohammed, 2001). It must, however, correspond
to the negative subject prefix in accordance with the agreement principle as
illustrated in (18) for the verb pik-a (cook).
(18) Si-pik-i (‘I don’t cook’)
Ha-tu-pik-i (‘we don’t cook’)
Hu-pik-i (‘You don’t cook’)
Ha-m-pik-i (‘You (pl) don’t cook’)
Ha-pik-i (‘S/he doesn’t cook’) Ha-wa-pik-i (‘They don’t cook’)
The following sections discuss the bilingual/multilingual situation in Kenya
from which the participants in this study are drawn, and provide as an overview
of relevant studies in bilingual/ multilingual aphasia.
1.3
Bilingualism/multilingualism and aphasia
The two terms bilingual and multilingual are used interchangeably in this study
to refer to speakers who use two or more languages or dialects in their everyday lives (Grosjean, 1994). Non-standard dialects of languages were previously
24
CHAPTER 1. INTRODUCTION
not considered to be distinct languages for purposes of discussing bilingualism. However, this has turned out to be mere cultural bias. Fabbro (1999)
clarifies that the distinction between language and dialect is at times only political, hence not relevant to linguistic or neurolinguistic research and practice.
Presently, most books on bilingualism and multilingualism point out that more
than half of the world’s population is bilingual or multilingual (e.g., Albert and
Obler, 1978; Grosjean, 1994; Fabbro, 1999). In Kenya, the country in which
this project was conducted, the majority of the citizens are either bilingual or
multilingual speakers of Swahili and English in addition to one or more of the
42 native languages.
Like bilinguals in other societies, Kenyans acquire and use their languages
for different purposes, in different domains of life and with different people.
Both Swahili and English share the same status as second languages, acquired
after the age of four, after the native language acquisition by the majority of
Kenyans. The English language serves as the official language of instruction
in all institutions of learning from primary school to university; it is also the
language of news broadcasts, parliamentary proceedings and business. The
Swahili language, on the other hand, is the national language taught as one
of the subjects from kindergarten to university; it is the language of politics,
business and daily interactions of ordinary people from different ethnic backgrounds. Both languages are obligatory and examinable subjects in all primary
and secondary schools in the country. The additional 42 native languages are
acquired and used in rural regions within ethnic groups spread across the eight
provinces of Kenya.
Speech and language therapy for aphasia patients in Kenya poses a great
challenge for clinicians who unfortunately can usually only communicate effectively in English. This is due to the fact that the clinicians are usually from
other countries; hence they only focus on the English language of the patients
during therapy sessions. This is contrary to a declaration of the first international symposium on bilingual aphasia captured in a book that was edited by
Michel Paradis (1995): “Given what we know, it is no longer ethically acceptable to assess aphasic patients on the basis of the examination of only one of
their languages” (p.219). Fabbro (1999) further argued that it is wrong for clinicians engaged in diagnosis and therapy of language disorders to disregard the
principles of bilingual aphasia, given the reality that about half of the world’s
population is bilingual.
1.3. BILINGUALISM/MULTILINGUALISM AND APHASIA
25
For researchers, bilingual / multilingual individuals with aphasia provide
a unique opportunity to investigate the effect of brain damage in different
linguistic systems simultaneously. Currently, a considerable number of studies
on aphasia in bilingual populations exist (Albert & Obler, 1978; Paradis, 1995;
2001; Fabbro, 1999). However, no study has examined Swahili-English bilingual
aphasic speakers in Kenya. The next section gives an overview of some relevant
studies on bilingual aphasia.
1.3.1
Bilingual/multilingual aphasia
The studies on bilingual aphasia reported in the aphasiology literature have
shown that bilinguals with brain damage affecting language areas: (1) may lose
the ability to use all the languages they mastered and exhibit the same type of
aphasia in all languages; (2) may exhibit language disorders selectively affecting
one language, known as ‘selective aphasia’; (3) may exhibit different types of
aphasia affecting their different languages, known as ‘differential aphasia’; or
(4) may exhibit pathological switching and mixing of their known languages.
A crucial finding in bilingual aphasia studies is that for a vast majority of
multilingual individuals, the patient will suffer from the same type of aphasia in all languages, to a degree proportionate to their pre-morbid proficiency
(e.g., Charlton, 1964; Karanth, Ahuja, Nagaraj, Pandit & Shivashankar, 1991).
When it comes to the recovery pattern, it has been mentioned that the language to return first is most often the one used around the time of the aphasiaproducing incident or the first-learned language (Obler & Albert, 1996; Obler
& Mahecha, 1991).
Prins and Bastiaanse (2006) described one of the first cases of bilingual
aphasia as reported by Johannes Wepfer, a German army surgeon, in 1683.
Wepfer’s stroke patient, R.N.N., was a 53-year-old bilingual speaker of Latin
and German diagnosed with anomic aphasia that lasted between 2 to 3 days.
After a month, however, R.N.N., exhibited other aphasic symtoms that were
diffult to classify. He could not recall names of others nor express his own
name, he had word finding difficulties (especially “little words”), his words were
incomplete, and most often his utterances were “alien and incoherent” (paraphasias) and violated the rules of grammar and word order by “pre-posing one
word to another”, especially in German. Based on these symptoms, Whitaker
(1998) considers this patient to have suffered from agrammatic aphasia, wheareas Prins and Bastiaanse (2006) argue that this might have been a case of fluent
26
CHAPTER 1. INTRODUCTION
aphasia with paragrammatism.
The first case of qualitatively differential aphasia was reported by Albert
and Obler (1978) who described a 35-year-old bilingual aphasia patient exhibiting Broca’s aphasia in Hebrew and Wernicke’s aphasia in English. The authors
claim that the patient understood but hardly spoke Hebrew, and that it was
the reverse for English. They further reported that the patient’s other languages, Hungarian and French, were mildly impaired. The authors therefore
concluded that there must be a separate cerebral localization of English and
Hebrew in this patient, suggesting the possibility of separate neuroanatomical
representations for languages known by bilingual/multilingual speakers.
A case of selective aphasia was reported a few years later by Paradis and
Goldblum (1989). They presented a bilingual aphasia patient who exhibited
selective aphasia in one of his languages after neurosurgery. The patient’s
first post-operative assessment indicated he had Broca’s aphasia in Gujarati,
whereas both French and Malagasy were intact. A follow up assessment some
years later showed full recovery of all languages. The authors concluded that
the most reliable interpretation of selective aphasia proceeds from neurofunctional grounds rather than neuroanatomical ones, as proposed by Albert &
Obler (1978). Paradis and Goldblum (1989) likewise argued that the languages
known by bilinguals separate primarily at the functional level, with each language using a distinct and independent neurofunctional system.
The first case of pathological mixing of the languages known by a bilingual
aphasia patient was reported by Stengel and Zelmanowicz (1933). They presented the case of a 57-year-old Czech patient named M.M. who was competent
in both Czech and German prior to her aphasia onset. M.M. was admitted to
a neurological clinic due to episodes of ‘cephalea’ (pain in the head) and word
finding difficulties. On assessment, she showed very poor verbal expression,
marked by grammatical errors and numerous phonemic and verbal paraphasias.
She was also mixing German and Czech, in which neither of the two languages
prevailed over the other. When M.M. could not find a word in one language, she
used the corresponding word in the other language without hesitation. M.M.’s
comprehension of both languages was found to be intact, even during complex
instructions.
Having briefly highlighted a few cases of aphasia in bilingual/multilinguals,
an account of agrammatism in bilingual aphasia is provided in the following
section.
1.3. BILINGUALISM/MULTILINGUALISM AND APHASIA
1.3.2
27
Agrammatism in bilingual/multilingual aphasia
Grammatical deficits in aphasia are known to depend on the structure of each
language system (Paradis, 1988). Grodzinsky (1991; 1999) argues that the
pattern of omissions and substitutions of grammatical morphemes that characterises agrammatism is dependent on the morphological structure of the language. In languages where omission of bound grammatical morphemes results
in a word, agrammatic speakers are likely to omit the grammatical morphemes,
whereas in languages where omission of bound grammatical morphemes results
in a non-word, the agrammatic speakers are likely to substitute the morpheme.
Alajouanine (1963) also argued that aphasic speakers of a language with vulnerable inflectional morphology show outstanding signs of agrammatism.
According to Fabbro (2001), the differences in manifestation of agrammatism in the different languages of bilinguals are insignificant and occur largely
at the surface level. He argues that the general characteristics of agrammatism
are universal and that most often, aphasia affects the grammatical aspects of a
language at different levels of severity. He reported a study in which 20 bilingual agrammatic speakers of Friulian (morphologically-rich) and Italian were
investigated. 13 patients (65%) showed similar impairments in both languages,
4 patients (20%) showed greater impairment of L2, while 3 patients (15%)
showed a greater impairment of L1. The parallel impairment in both languages
confirms Paradis’ (1988) hypothesis that grammatical disorders in aphasia depend on individual language structure. Fabbro’s further analysis revealed that
agrammatic Friulian and Italian speakers had similar grammatical errors in
both languages, with only minor differences in areas where the two languages
differ. The patients frequently omitted free-standing grammatical morphemes
and substituted bound grammatical morphemes in both languages. The most
remarkable difference was found to be the proportion of omissions of obligatory pronouns in Friulian (38.25%) vs. Italian (1.25%) which was attributed
to the particular grammatical structures of the two languages. For instance, in
Friulian the subject is always accompanied by an obligatory pronoun (Il frut al
bef : ‘The boy he drinks’), whereas in Italian the subject pronoun is dropped
(Il bambino beve: ‘The child drinks’ or beve: ‘ he/she drinks’). Consequently,
the bilingual agrammatic speaker can easily avoid structures with pronouns in
Italian, but not in Friulian (Fabbro & Frau, 2001).
The present project focuses on grammatical aspects in Swahili-English bilingual agrammatic speakers to determine how agrammatism manifest itself in two
28
CHAPTER 1. INTRODUCTION
morphologically different languages. The next section provides an overview of
the relevant studies on verb deficits and word order in agrammatism, with
corresponding linguistic accounts.
1.4
Verb and word order deficits in agrammatic
aphasia
Verb and word order deficits have frequently been reported in aphasia literature, however, there is no consensus the underlying deficit in agrammatic
aphasia. In general, verbs have been found to be more vulnerable than nouns
in Broca’s aphasia (Berndt, Mitchum, Haendiges & Sandson, 1997; Miceli, Silveri, Villa & Caramazza, 1984; Semenza, Luzzati & Carabelli, 1997; Jonkers &
Bastiaanse, 1998; Kim & Thompson, 2000) although other studies have found
that both nouns and verbs may be equally impaired (Basso, Razzano, Faglioni
& Zanobio, 1990; Berndt & Haendiges, 2000; Caramazza & Hillis, 1991), at
least in some patients.
One of the key findings in recent studies focusing on verb and word order
deficits in agrammatic aphasia is that verb inflections for tense and/or time reference in both spontaneous speech and controlled experiments are difficult, and
that derived word order sentences, especially in controlled experimental studies,
are impaired. Studies in different languages have shown tense to be particularly
vulnerable in sentence production and sentence anagram tasks for agrammatic
speakers (Dutch: Bastiaanse, 2008; Kok, van Doorn & Kolk, 2007; English:
Arabatzi & Edwards, 2002; Dickey, Milman & Thompson, 2005; Faroqi-shah
& Thompson, 2007; German: Burchert et al., 2005; Wenzlaff & Clahsen, 2004;
Greek: Nanousi et al., 2006; Stavrakaki & Kouvava, 2003; Varlokosta, Valeonti,
Kakavoulia, Lazaridou, Economou & Protopapas, 2006; Hebrew: Friedmann &
Grodzinsky, 1997; Turkish: Bastiaanse et al., 2011; Yarbay Duman & Bastiaanse, 2009). However, agreement inflection has also been reported to be
affected in studies of some languages (Dutch: Bastiaanse 2008, English: Lee
et al., 2008, German: Burchert et al., 2005). From this body of research, the
authors provide several explanations for the tense problems which are captured
in aforementioned linguistic theories of agrammatism.
The first group of authors relates the problem to the position of tense in
the syntactic tree, which is assumed to be pruned from the tense node upwards
1.4. VERB AND WORD ORDER DEFICITS IN AGRAMMATIC APHASIA
29
(Friedmann, 2002; Friedmann & Grodzinsky, 1997). Several other studies, however, have challenged this view by showing different patterns of impairments
involving different parts of the syntactic tree. The second group of authors argues against the missing parts of a syntactic representation, and suggests that it
is instead the interpretable features of tense that are underspecified (Burchert
et al., 2005; Nanousi et al., 2006; Wenzlaff & Clahsen, 2004). Burchert and
colleagues (2005) point out that both tense and agreement may be underspecified for patients with agrammatism. The final group of authors suggests that
the problem with tense is neither due to its position on the syntactic tree nor
an issue of underspecification, but is rather related to time reference (Bastiaanse, 2008; Bastiaanse et al., 2011; Yarbay Duman & Bastiaanse, 2009). This
is because there is evidence that not all forms of tense (past, present and future) are equally affected, and that nonfinite verb forms are affected as well.
The problem arises mainly when expressing time reference to the past through
tensed verbs or untensed participles. They argue that the selective problem
with tense results from affected discourse syntax processing, rather than its
position in the syntactic tree or being underspecified. This theory is further
explored extensively in chapters 2 and 3.
Studies in a number of languages have also shown that derived order sentences are problematic for agrammatic speakers (English: Caramazza & Zurif,
1976; Grodzinsky, 2000; Bastiaanse & Thompson, 2003; Bastiaanse & Edwards,
2004; Dutch: Bastiaanse et al., 2002; 2003; Bastiaanse & Van Zonneveld, 2005;
German: Burchert, Meisner & De Bleser, 2008; Turkish: Yarbay Duman &
Bastiaanse, 2007; Yarbay Duman, Altınok, Özgirgin & Bastiaanse, 2011). Sentence structures such as passives, object relatives, and sentences with scrambled
objects or moved verbs have been found to cause problems in both comprehension and production. There are different explanations as to why agrammatic
speakers have difficulties with derived order more than base order sentences.
One set of researchers attributes this difficulty to compromised mapping
of thematic roles (agent, theme) onto grammatical roles (subject, object, byphrase: Linebarger, Schwartz & Saffran, 1983; Schwartz, Linebarger, Saffran &
Pate, 1987). Another group of researchers suggest that the problem arises from
missing traces in agrammatic language representation (Grodzinsky 1995; Drai
& Grodzinsky 2006). Traces are crucial for assigning thematic roles to sentence
arguments which are not in their base positions. The authors assert that these
traces are not available to agrammatic speakers; the speakers thus apply a de-
30
CHAPTER 1. INTRODUCTION
fault strategy by assigning thematic roles to noun phrases strictly on the basis
of their position in the sentence. However, several studies have contradicted
this theory by demonstrating that traces are actually intact in agrammatic linguistic representation (Dickey, Choy & Thompson, 2007; Thompson & Choy,
2009; Choy & Thompson, 2010). Finally, some researchers argue that the derived order sentences are a problem for agrammatic speakers, not only in comprehension but also in production, because constituents that naturally belong
together are separated from one another in derived order sentences (Bastiaanse
& Van Zonneveld, 2005; Bastiaanse & Thompson, 2003; Yarbay Duman et al.,
2007; 2011). In chapters 4 and 5, we provide two studies that tested this theory
and also present an extensive discussion on this topic.
In summary, it is clear from this brief review that there is a consensus
among researchers that verb inflection and word order pose great challenges to
agrammatic speakers. The linguistic accounts reviewed earlier in this chapter
make several predictions regarding agrammatic speakers’ performance based on
data largely gathered from monolingual populations. While the TPH, TUH and
TAUH predict a general problem with tense inflection, the PADILIH predicts a
selective problem with past time reference through verb inflection, irrespective
of whether it is expressed through tense or aspect or whether finite verbs or
periphrastic verb forms are used. Moreover, both the TDH and DOP-H predict problems with sentence structures whose arguments are in derived order.
While TDH predicts problems only in comprehension, DOP-H predicts problems in both comprehension and production of sentences with a derived order
of arguments. The question is: what kind of pattern will emerge in bilingual
speakers of two morphologically different languages?
Despite all that has been learned in recent years, the linguistic account that
gives the exact nature and a precise characterization of the underlying verb and
word order deficits in agrammatic aphasia is still a matter of controversy. The
next section presents the research questions that guided the current project.
1.5
The Research Questions
Apart from the fact that the studies on verb and word order deficits in agrammatic aphasia reviewed in the previous sections are predominantly monolingual
aphasia studies, the languages examined so far are mainly Indo-European languages. It is against this backdrop that we proposed a study that involves bilin-
1.5. THE RESEARCH QUESTIONS
31
gual agrammatic speakers, who, moreover, speak English and Swahili; that is,
an Indo-European and a Bantu language. These two languages, contrasting in
terms of verbal morphology, provide a valuable site to investigate how agrammatism manifests itself in this bilingual population in light of the linguistic
theories discussed.
The following questions are addressed in this thesis:
1. Are there similarities or differences in the speech production of monolingual and bilingual aphasic speakers of English?
2. What are the features of Swahili agrammatic speech? Are they comparable with those of English agrammatism?
3. What are the agrammatic speakers’ patterns of production of verb morphology for tense and time reference in Swahili and in English? Are verb
forms referring to the past impaired?
4. Is production of time reference to the past through verb inflection impaired in both languages of Swahili-English bilinguals?
5. Is comprehension of time reference to the past through verb inflection
impaired in both languages of Swahili-English bilinguals?
6. Is reference to the past similarly impaired in both Swahili and English?
7. Is comprehension of sentences whose arguments are in a derived order
impaired in both languages of Swahili-English bilinguals?
8. Is production of sentences whose arguments are in a derived order impaired in both languages of Swahili-English bilinguals?
These questions are addressed in the four studies described in this thesis.
The first study, presented in Chapter 2, focuses on the first three questions
listed above. It identifes the features of Swahili agrammatic speech and compares the use of verb inflections for tense and time reference between agrammatic and non-brain-damaged individuals. The second study, addressing questions 4-6, focuses on time reference problems in both languages of SwahiliEnglish bilingual agrammatic speakers. Both the third and fourth studies
examine word order problems in Swahili-English bilingual agrammatic individuals. While the third study addresses sentence comprehension difficulties
32
CHAPTER 1. INTRODUCTION
(question 7), the fourth study addresses sentence production problems (question 8). The final chapter discusses the major findings of the thesis and issues
arising from the studies. It concludes with a discussion of the clinical implications of the study and recommendations for future research.
CHAPTER
2
Characteristics of Swahili-English Bilingual Agrammatic
Spontaneous Speech and the Consequences for
Understanding Agrammatic Aphasia
Abstract
Most studies on spontaneous speech of individuals with agrammatism have focused almost exclusively on monolingual individuals. There is hardly any previous research on bilinguals, especially of structurally different languages; and
none on characterization of agrammatism in Swahili. The current study identifies the features of Swahili agrammatic narrative and spontaneous speech, and
compares the use of verb inflections for tense and time reference in English and
Swahili in six bilingual agrammatic speakers and 12 non-brain-damaged speakers matched on age, native language and education level to the agrammatic
speakers. The results show a remarkable similarity between the agrammatic
phenomena in both languages on the typical agrammatic features: utterance
This study has been published as:
Abuom, T. & Bastiaanse, R. (2012). Characteristics of Swahili-English bilingual agrammatic spontaneous speech and the consequences for understanding agrammatic aphasia.
Journal of Neurolinguistics 25, 276-293.
33
34 CHAPTER 2. CHARACTERISTICS OF SWAHILI-ENGLISH AGRAMMATISM
length and speech rate are reduced and the proportion of grammatical sentences and complex sentences is lower than normal. Analysis of verb inflection
demonstrates that there are no qualitative differences between the Swahili and
English samples: in both languages reference to the past is more impaired than
reference to the present. However, the use of verb inflection in general is better preserved in Swahili than English. English verb inflections are frequently
omitted, whereas Swahili verb inflections are substituted.
The implications of these findings for theories on agrammatism are discussed.
2.1
Introduction
In the neurolinguistic literature, several studies report how agrammatism manifests itself in the spontaneous speech of individuals with Broca’s aphasia (see for
English: Menn & Obler, 1990; Saffran, Berndt & Schwartz, 1989; Thompson,
2003; for Dutch: Bastiaanse & Jonkers, 1998; for Italian: Miceli, Mazzucchi,
Menn & Goodglass, 1983; Rossi & Bastiaanse, 2008; for Indonesian: Anjarningsih, 2012; Anjarningsih & Bastiaanse, 2011). An overview of the findings
of these studies consistently reveals a pattern of linguistic deficits: slow, halting, labored, non-fluent, telegraphic speech with omissions and/or substitutions
of bound and free grammatical morphemes, while comprehension is relatively
spared. The usage of verb morphology is impaired: verb inflections are often
omitted or substituted and non-finite verbs are overused (Saffran et al., 1989;
Bastiaanse, Hugen, Kos & Van Zonneveld, 2002). While this body of research
has contributed substantially to our understanding of the spontaneous speech of
aphasic speakers, it has focused almost exclusively on monolingual individuals;
there is hardly any previous research on bilinguals, especially of structurally
different languages. The current study focuses on agrammatism in bilingual
speakers of Swahili and English, two languages which possess contrasting morphological and syntactic properties. Considering that languages differ largely
in terms of grammatical morphology, the same underlying deficit may cause different surface manifestations in the different languages of a bilingual (Paradis,
1988). Given this assumption, the aim of the current study is three-fold. First,
we would like determine whether there are similarities or differences in English
speech production in monolingual and bilingual aphasic speakers. This will
determine whether the analysis of spontaneous speech in languages for which
2.1. INTRODUCTION
35
aphasia tests are not available is sufficient to identify agrammatism. Second,
we want to identify the features of Swahili agrammatic speech and compare
them with those of English agrammatic speech. The final goal is to compare
the agrammatic speakers’ production of verb morphology and time reference
in both Swahili and English. As these languages differ significantly in their
morpho-syntax, these data provide a valuable site for testing the claim that
reference to the past is impaired. We will determine whether reference to the
past is impaired as has been shown in several experimental studies.
We start by giving some background on cross-linguistic variation in aphasia
symptoms. Next, we provide a brief overview of bilingual aphasia. This will
be followed by a neurolinguistic characterization of agrammatic speech and an
introduction to relevant features of Swahili. We conclude by providing the
research questions and expectations of the current study.
2.1.1
Cross-linguistic variations in aphasia symptoms
Aphasia research across languages has led to some important assumptions concerning the language-specific factors that influence how the same underlying
deficit may cause different surface manifestations of agrammatism in different languages. Such factors are related to linguistic complexity, the semantic
importance of a morpheme, and to whether or not uninflected forms are permitted. Menn and Obler (1990) presented data from a cross-linguistic study
on agrammatic production in 14 different languages. Their key findings are
that grammatical morphemes such as plural endings, past-tense endings, and
auxiliary verbs are generally prone to errors. Free grammatical morphemes
tend to be omitted, whereas bound grammatical morphemes are substituted in
agrammatic production. In a language such as English, agrammatic speakers
tend to omit word endings such as markers of plural, past tense, and verb 3rd
person singular. However, in a language like Italian where every noun, verb,
adjective has an ending, agrammatic speakers tend to make substitution errors
rather than omission errors. They concluded that the presence or omission of
grammatical morphemes is determined by their semantic importance; and that
grammatical morphemes which are part of an extensive paradigm are likely
to be prone to more errors. Grodzinsky’s (1991; 1999) and Paradis’ (1995),
however, argue that grammatical deficits in aphasia, specifically the omission
and / or substitution of grammatical morphemes that characterise agrammatism, depend on the structure of each language. In languages where omission of
36 CHAPTER 2. CHARACTERISTICS OF SWAHILI-ENGLISH AGRAMMATISM
bound grammatical morphemes results in a word (as in the case of English, for
instance ‘-ed’ in picked ), agrammatic speakers are likely to omit the grammatical morphemes, whereas in languages where bound grammatical morphemes
results in a non-word the agrammatic speakers are likely to substitute the morpheme with another (as in Swahili for instance, ‘ku’ and ‘-a’ in ‘ku-pig-a’ ‘to
hit’, ‘pig’ is a non-word in Swahili). In other words, the manifestation of grammatical errors depends on whether or not the uninflected forms are permitted.
Fabbro (2001) proposes that the nature of agrammatism has a universal character and follows the rule whereby aphasia impairs all grammatical aspects of
a language, even if at varying degrees of severity.
2.1.2
Bilingual aphasia
The term ‘bilingual’ has been used in this study to refer to all those people
who use two or more languages or dialects in their everyday lives (Grosjean,
1994). Presently, most work on bilingualism and multilingualism suggests that
more than half the world population is bilingual or multilingual, and that the
vast majority of bilingual aphasic individuals suffer from the same type of
aphasia in all their languages mastered pre-morbidly (for example, Charlton,
1964; De Diego-Balaguer, Costa, Sebastián-Gálles, Juncadella & Caramazza,
2004; Fabbro, 2001; Faroqi-Shah & Waked, 2010; Knoph, 2011). The most
relevant issue in bilingual aphasia concerns differences in the pattern of recovery
across the languages mastered by the bilingual speakers (see Fabbro, 2001;
Paradis, 2001). The common pattern of recovery following the aphasia incident
is parallel recovery where all languages of a bilingual are equally affected and
recovery is similar. Should there be a difference in recovery; the difference may
only reflect a difference in premorbid proficiency level between the languages
mastered. Another pattern is differential recovery where the language likely
to return first is either one learnt first, or used most frequently prior to the
insult (Albert & Obler, 1996). In our case, the bilinguals in this study acquired
English and Swahili early (from around the age of four), and were pre-morbidly
highly proficient in all their languages.
With respect to manifestations of aphasia across the languages of a bilingual individual, Paradis (1988) argues that in languages which differ largely
in grammatical morphology, the same underlying deficit may cause different
surface manifestations. Some recent studies show that the rich morphology of
one language may be better preserved than the poor morphology of the other
2.1. INTRODUCTION
37
language. Knoph (2011), for example, found the complex Farsi morphology
better preserved than the comparatively simpler Norwegian morphology in a
Farsi-Norwegian bilingual agrammatic speaker, pre-morbidly proficient in both
Farsi and Norwegian. Alexiadou and Stavrakaki (2006) and Abuom, Obler and
Bastiaanse (2011) showed the same pattern for pre-morbidly proficient GreekEnglish and Swahili-English bilingual agrammatic speakers respectively: the
more complex the morphological paradigm, the better it is preserved.
One should keep in mind, however, that morphologically rich paradigms are
usually more regular than morphologically simple paradigms. It may thus be
the case that it is not a matter of complexity but rather of regularity (Goral,
2011). Bybee (2007) proposes two morphological processes in relation to morphologically rich and complex paradigms: the regular morphological process,
which is affixal and often agglitunative in nature; and the irregular morphological process, which often involves changes in the stem or high degree of fusion
between stem and affix. Regularity is associated with affixation, whereas irregularity is associated with internal stem change. While affixation has been
claimed to be more ‘natural’ and highly frequent in most languages, and hence
easier to process in general, internal stem changes (irregularity) are considered
less ‘natural’, lexically arbitrary and of low type frequency, and hence more
difficult to master (Dressler 1985; Bybee, 2007). In situations of linguistic limitations, such as in children with SLI, bilinguals with (L1) attrition (language
loss) and individuals with aphasia, high-frequency linguistic items have been
found to be resistant to dissolution and are preferred in oral expression (see
Centeno & Anderson, 2011).
2.1.3
The syntactic, lexical and morphological deficits in
agrammatic aphasia
The spontaneous speech of agrammatic speakers is non-fluent. At the syntactic level, agrammatic speech is characterized by short and / or fragmentary
utterances with frequent omissions of function words, such as prepositions,
pronouns, articles, particles, conjunctions, and determiners (Menn & Obler,
1990). As a result, significantly fewer words are produced per utterance, generally expressed by a shorter Mean Length of Utterance (MLU: see Rossi and
Bastiaanse, 2008; Sanchez, 1996; Thompson, Shapiro, Li & Schendel, 1995; Vermeulen, Bastiaanse & Van Wageningen, 1989). Furthermore, a close scrutiny
of the structural quality of the agrammatic productions in previous studies re-
38 CHAPTER 2. CHARACTERISTICS OF SWAHILI-ENGLISH AGRAMMATISM
veals two prominent features: the limited use of embeddings in sentences and
the production of large proportions of ungrammatical sentences (Saffran et al.,
1989; Bastiaanse et al., 2002). Moreover, a clear preference for shorter sentences
with verbs with fewer internal arguments than normal has also been found (see
Thompson, Lange, Schneider & Shapiro, 1997; Bastiaanse and Jonkers, 1998;
Rossi and Bastiaanse, 2008).
At the lexical level, it has been reported that nouns are produced to a
normal extent, but fewer verbs and / or a lower diversity than normal are
produced (e.g. Bastiaanse & Jonkers, 1998; Menn & Obler, 1990; Saffran,
Berndt & Schwartz, 1989). However, Lorch (1990) found that the production
of verbs and verb-types was spared in some of the agrammatic speakers in their
cross-linguistic study of Hindi, Icelandic and Finnish, while Crepaldi, Ingignoli,
Verga, Contardi, Semenza, and Luzzatti (2011) did not report a noun-verb dissociation in Italian agrammatic speech. There are also reports of a normal use
of verbs in Indonesian agrammatic spontaneous speech (Anjarningsih, 2012),
but Indonesian is a language without verb inflection for tense and agreement,
which may explain these results.
At the morphological level, the problems are clearly visible in verb inflection:
the proportion of inflected verbs is low (Saffran, et al., 1989, Thompson et al.,
1994), although this inflectional problem may be restricted to finite verbs, that
is, verbs that are inflected for Tense, Aspect and Agreement and excluding
participles or gerunds (Bastiaanse et al., 2002).
Experimental data show that not all verb inflections (Tense, Agreement,
Aspect, Mood) are equally vulnerable. According to Friedmann and Grodzinsky (1997) and Wenzlaff and Clahsen (2004), agreement inflection is spared
but tense inflection is impaired. Clahsen and Ali (2009) showed that Mood
is spared and Nanousi, Masterson, Druks and Atkinson (2006) showed that in
Greek Aspect is impaired, whereas Tense and Agreement are relatively spared.
And recently, our group reported for several languages that it is particularly
reference to the past, by Tense and Aspect, that is impaired in agrammatism
(Abuom et al. 2011, for English; Bastiaanse 2008 and Jonkers & De Bruin
2009, for Dutch; Bastiaanse, Bamyaci, Hsu, Lee, Yarbay Duman & Thompson
2011, for Chinese, English and Turkish; Yarbay Duman & Bastiaanse 2009 for
Turkish).
Little is known about reference to the past in agrammatic spontaneous
speech; however, a few studies specifically mention problems with the time
2.1. INTRODUCTION
39
reference of verb inflection. Simonsen and Lind (2002) described a Norwegian
agrammatic speaker who used very few verbs and hardly any past tense forms
in his spontaneous speech. Similarly, Stavrakaki and Kouvava (2003) reported
on two agrammatic Greek speakers who have problems producing verb forms
with perfect aspect. Beeke, Wilkinson and Maxim (2003a) analyzed the conversation data of a monolingual agrammatic speaker of English who, they report,
frequently produced either a present tense verb or an infinitive in place of a future tense verb or past tense verb. Note that both past tense verbs and perfect
aspect verbs refer to events taking place or performed in the past.
These data underlie the PAst Discourse LInking Hypothesis (PADILIH).
This hypothesis is based on Avrutin’s (2000; 2006) idea that linking at the
discourse level is done by ‘discourse syntax’ and linking at the sentence level
is done by ‘narrow syntax’. According to Avrutin (2000; 2006) processing by
discourse syntax is difficult for individuals with agrammatic speakers compared
to processing by narrow syntax. Discourse linking requires more processing
resources which agrammatic individuals lack. According to Zagona (2003),
present tense is locally bound (or in Avrutin’s terminology, is processed by
‘narrow syntax’), since the time of the event and the time of speaking coincide.
Past tense, however, is discourse linked (in Avrutin’s terminology, is processed
by ‘discourse syntax’). Bastiaanse et al. (2011) modified Zagona’s (2003)
theory and state that it is not past tense that requires discourse linking, but all
verb forms that refer to the past, including, for example, the present perfect.
For instance, in a sentence such as ‘the boy has written a letter’; the event took
place in the past, although ‘has’ is present tense. The PADILIH, thus, predicts
that Kenyan bilingual agrammatic speakers will have more problems producing
verb forms referring to the past than verb forms referring to the future.
2.1.4
Relevant features of Swahili
Swahili is a Bantu language, highly agglutinative and classified as an SVO language (Ashton, 1982). It is widely spoken in most African countries, including
Kenya where this study was conducted. Kenya is a multilingual society with
an average person speaking at least three languages. The two most dominant
languages across the population are Swahili and English, but most Kenyans
speak one of the 42 languages linguists term “ethnic languages” at home as
well. Each of the 42 languages is classified either as Bantu, Nilotic, or Cushitic.
Swahili and English have the same status as second languages since both are ac-
40 CHAPTER 2. CHARACTERISTICS OF SWAHILI-ENGLISH AGRAMMATISM
quired around the age of 4, after native language acquisition by the majority of
Kenyans. Swahili is the national language taught as one of the subjects from
kindergarten to university; it is the language of politics, business, and daily
interactions of people from different ethnic backgrounds. English is used as
the official language of instruction in all educational institutions from primary
school to university; it is also the language of news broadcasts, parliamentary
proceedings, and business. Therefore, an adult with over 12 years of uninterrupted education in Kenya is generally expected to be equally highly proficient
in both languages.
Swahili has a fixed word order (SVO) at the sentence level, where the subject precedes the verb and the object (see 1). Within constituent phrases,
modifiers follow the head. Therefore adjectives, pronouns, determiners etc.,
follow the nouns they modify while adverbs come after the verb. As in English,
Swahili clause structure generally consists of a subject and a predicate. The
subject always precedes the predicate (Mohammed, 2001). Swahili has three
different types of sentences: a simple sentence that consists of a single clause; a
complex sentence that consists of one main clause and at least one subordinate
clause which obligatorily follows the main clause, and a compound sentence
that consists of at least two main clauses joined by a coordinating conjunction.
However, the most distinguishing feature of Swahili is its verbal system.
(1)
Mama a-li-m-piga
kijana
Mother she-Past-him-hit boy
“The mother hit the boy”
The Swahili verbal system is distinctly more complex than that of English,
consisting of numerous affixes, both inflectional and derivational morphemes,
attached to the verb root. These affixes (prefixes, infixes and suffixes) occupy
specific positions and perform specific functions. The general position scheme
of the affixes in relation to the verb root is shown in (1a). Some illustrations
from Abuom et al. (2011) are given in (2b-d).
(2)
(a)
Pre-prefix (Pp) + Subject prefix (Sp) + Tense marker (T) + Object
infix (Oi) + ROOT + derivation (d) + Suffix (s) + Post-suffix (Ps).
2.1. INTRODUCTION
(b)
41
A + li + m + pig
+ a
Sp + T + Oi + ROOT + d
“S/he hit him/her”
(c)
Ha + tu + ta + m + pig
+ a
Pp + Sp + T + Oi + ROOT + d
“We will not hit him/her”
(d)
Tu + na + pig
+ a + n + a
Sp + T + ROOT + d + S + Ps
“We are hitting each other”
A Swahili verb complex, due to its agglutinative feature unlike that of English, can function as a complete sentence as illustrated in (2b-d). In the
verbal complex, the subject prefix (subject-verb agreement), the tense marker
(includes tense and aspect) and the verb root are generally obligatory in every grammatical Swahili sentences. Both the subject prefix and object infix
must agree in number with subject and object of the sentence respectively,
for instance in (1).Tense and aspect inflections are critical to time reference
in Swahili. As illustrated in (2b-d), Swahili has three marked tenses: past,
present and future. The past tense marked by ‘li’ describes a past activity
without reference to a specific time as in (2b). The future tense marked by ‘tu’
describes events predicted to follow the present time as in (2c). English, on
the contrary, has no verb inflection for future tense. The Swahili present tense
is marked by either ‘-a-’ or ‘-na-’ : both can used interchangeably to describe
actions that take place at the time one is speaking as in (2d).
Other inflections that are considered to be ‘neutral’ tense markers are the
infinitive, which is generally marked by the prefix ‘ku’ attached to verb root,
and the narrative or consecutive marker ‘ka’, which generally express an action
or state which follows another action as in (2e). For aspect in Swahili, the
present perfect marker ‘me’ is also frequently used to describe a past activity
which has relevance to the present time and is comparable to the present perfect
in English as in (2e).
(2e) A-me-ruka
chini a-ka-kimbia
ku-cheza mpira
He-Pres.perf.-jump down he-Cons.-ran off INF.-play football
“He has jumped down, he (then) ran off to play football”
42 CHAPTER 2. CHARACTERISTICS OF SWAHILI-ENGLISH AGRAMMATISM
Other types of verbs are the copulas and auxiliaries. Copulas in Swahili, as
in English, are known to have little independent meaning, and mainly function
to relate sentential elements of clause structure especially subject and complement (3a). Just like in English, Swahili modal verbs accompany lexical verbs
(3b), but, unlike in English, Swahili modal verbs are inflected for Agreement.
Auxiliaries such as ‘to have’ and ‘to be’ that are used in combination with a
participle, do not exist in Swahili.
(3)
(a)
Kenya ni nchi
kubwa
Kenya is country big
“Kenya is a big country”
(b)
Mgonjwa a-na-weza
kunywa maziwa
patient
he-Pres.-can drink
milk
“The patient can drink milk”
2.1.5
The research questions and expectations
The current study contributes to aphasiology as a field of research in two ways:
Firstly, it provides further evidence of features of agrammatism from a previously undescribed language; secondly, it gives an insight into the patterns
of manifestation of agrammatism in bilingual individuals speaking two structurally different languages. This has been achieved by addressing three main
research questions:
1. Are there similarities or differences in the English speech production of
monolingual and bilingual aphasic speakers?
2. What are the features of Swahili agrammatism? Are they comparable
with those of English agrammatism?
3. What are the agrammatic speakers’ patterns of production of verb morphology for tense, and time reference in Swahili and in English? Are verb
forms referring to the past impaired?
First, we compared the English samples of narrative speech of Kenyan bilingual agrammatic speakers with those of monolingual American agrammatic
speakers from Thompson, Choy, Holland & Cole (2010). This was done to
2.1. INTRODUCTION
43
determine whether the analysis of spontaneous speech in languages for which
aphasia tests are not available is sufficient to identify agrammatism. We expected similar manifestation of agrammatism in English language between the
two groups irrespective of number of languages mastered pre-morbidly.
To answer the second question on features of Swahili agrammatism, the
Swahili and English samples of the bilingual Kenyan agrammatic speakers were
analyzed on a number of variables that are relevant to quantify agrammatic
aphasia: the mean length of utterances (MLU), speech rate (words per minute),
number and diversity of nouns and verbs, the use of copulas and auxiliaries,
and the percentages of ungrammatical and embedded sentences. We first made
comparisons between samples of agrammatic speech and those of non-braindamaged speakers in Swahili and English. We expected differences between
the two groups on each of these variables. We then compared the agrammatic
performance on these variables between Swahili and English. If the underlying
disorder is the same in both languages, which is likely because we compared
within individuals (Fabbro, 2001; Faroqi-Shah & Waked, 2010), it was expected
that the reduction in utterance length and the delay in speech rate, as well as
the degree in which nouns and verbs are produced would be similar in both
languages. Also, we expected the agrammatic speakers to produce more ungrammatical sentences and fewer embedded sentences than non-brain-damaged
control speakers in both languages.
The final question is how the bilingual agrammatic speakers perform on
a variable that is fundamentally different in the two languages. Comparisons
were made between the use of verb inflections and time reference morphology.
Abuom et al. (2011) showed that, on a production experiment with two bilingual English-Swahili agrammatic speakers, verb inflection was better preserved
for Swahili than for English. It was argued that this was caused by the fact
that verb inflection is more anchored into the system in Swahili, with its very
rich verb inflection paradigm for tense and agreement. In English, the tense
and agreement paradigm is poor (restricted to -s, -ed), sometimes irregular and
less anchored in the system and, therefore, more vulnerable. Hence, we predict
that production of finite verbs (those verb forms that are inflected for tense and
agreement) will be relatively spared in Swahili (cf. Goral, 2011). It has also
been reported that agrammatic speakers produce fewer verb forms referring
to the past than non-brain-damages speakers, in spontaneous speech data (Simonsen & Lind, 2002; Stavrakaki & Kouvava, 2003), conversation data (Beeke,
44 CHAPTER 2. CHARACTERISTICS OF SWAHILI-ENGLISH AGRAMMATISM
Wilkinson and Maxim (2003a) and experimental data (Bastiaanse, 2008; Bastiaanse et al., 2011; Faroqi Shah & Dickey, 2009). We, therefore, predict that
production of verb forms referring to the past will be reduced, whereas production of present verb forms will be relatively spared. However, as mentioned,
in Abuom et al.’s (2011) experiment, the two bilingual English Swahili agrammatic individuals showed intact production of past tense in Swahili, but not
in English. This relatively better preservation of verb forms referring to the
past in Swahili may be reflected in spontaneous speech. Substitutions of verb
inflections are expected to occur in Swahili, whereas omissions are expected in
English (Grodzinsky, 1991; 1999; Paradis, 1995).
2.2
2.2.1
Methods and Procedures
Participants
The participants recruited for this study include 6 non-fluent aphasic/agrammatic speakers and 12 non-brain-damaged speakers (NBDs). Each
participant spoke either Bantu or Nilotic language as native language, but all
spoke English and Swahili as second languages. They were matched on age,
native language, and education (a minimum of O-Level qualification, equivalent to high school diploma). In the Kenyan school system, these are graduates
who have gone through kindergarten, elementary (primary school) and high
school tiers of the education system, which means 12 years of uninterrupted
exposure to English and Swahili. The agrammatic speakers were, therefore, premorbidly highly proficient in the two second languages. All participants were
right-handed and without a history of psychiatric or developmental speech or
language disorders or any other neurological conditions.
The aphasic speech produced was judged as ‘telegraphic’ by a speech therapist: it was perceived as being slow and effortful with short phrases consisting
of mainly content words. Unfortunately, in Kenya there are no tests available
to establish the aphasia syndrome. However, all agrammatic speakers had good
comprehension in both languages on an adapted version of the subtask for auditory comprehension of single words (nouns, verbs, colours, shapes, letters,
numbers) from the Boston Diagnostic Aphasia Examination word comprehension test (Goodglass & Kaplan, 1972). A few pictures of this task were substituted, because some items were unknown in Kenya and, hence, no Swahili word
2.2. METHODS AND PROCEDURES
45
was available (for example, a hammock was changed to a swing). It is however
important to note that the BDAE cannot be used to classify the aphasia type
in Kenya because of its cultural bias. The demographic details of the participants and their scores on the BDAE subtest for auditory word comprehension
are shown in the Table 2.1.
Table 2.1: The demographic details and the results on the test for auditory comprehension
of words (on an adapted version of the BDAE-test in Swahili and English) of the
agrammatic speakers and non-brain-damaged speakers.
Participant Age
Agrammatic
LA
43
MM
46
EA
40
HJ
45
JK
49
SW
20
NBD
IA
41
DM
49
MK
40
JN
46
NK
45
BK
20
GN
43
GK
44
MC
40
PK
39
BS
21
JR
48
2.2.2
Gender Handed- Education Years Native
ness
post language
stroke
F
F
M
F
M
M
R
R
R
R
R
R
16
16
16
12
17
12
F
M
M
F
F
M
F
F
M
M
F
M
R
R
R
R
R
R
R
R
R
R
R
R
17
16
16
15
16
12
16
15
17
12
14
16
1
16
17
10
1
2
Word comprehension
(maximum score: 72)
English
Swahili
Bantu
Nilotic
Nilotic
Nilotic
Bantu
Bantu
71.5
72
72
72
72
71.5
72
72
72
72
72
72
Nilotic
Bantu
Nilotic
Bantu
Bantu
Nilotic
Bantu
Bantu
Nilotic
Nilotic
Bantu
Nilotic
72
72
72
72
72
72
72
72
72
72
72
72
72
72
72
72
72
72
72
72
72
72
72
72
Materials
For elicitation of narrative speech, the methods of Olness (2006) were used.
Two pictures have been used, the Pulitzer Prize winning photograph by Annie
Wells of a girl being rescued from the water by a fireman and the cookie theft
picture from the BDAE (Goodglass & Kaplan, 1972). The participant was first
asked to describe the picture and then to make a story around it with a beginning, a middle and an end. Olness (2006) showed that when aphasic speakers
are asked to tell a story rather than to describe a picture, more variation in
46 CHAPTER 2. CHARACTERISTICS OF SWAHILI-ENGLISH AGRAMMATISM
verb forms occurs. Since our main interest was in the use of verbs and verb
inflection for time reference, this seemed to be an appropriate method. Additionally, a spontaneous speech interview was held with one question asking for
information from the past and one for information in daily life. The questions
were:
The flood rescue and the cookie theft
(a) Can you tell me what is happening in this picture?
(b) Can you create a story with the beginning, the middle and the end about
what happened in the picture?
Spontaneous speech
Reference to the past:
(a) Can you tell me about how your speech problems started (agrammatic
speakers)/ about your last illness (for NBDs)?
Reference to the present:
(b) Can you tell me about your current work / hobbies?
2.2.3
Procedures
Recording sessions were held in a quiet setting for each of the participants
using a digital audio recorder. For the agrammatic speakers, the interviews
in English and Swahili were done on different days, for the NBDs at different
times on the same day. To avoid code switching during recording sessions, the
participants were explicitly asked to speak only Swahili or only English. The
experimenter was very cautious to use only one language without intrusions
from the other. Half of the participants were first tested in English, half first
in Swahili.
The order of the elicitation was similar for each participant: first the ‘flood
rescue’ picture, followed by the ‘cookie theft’. The interview was done last. The
questions were always in the same order, that is, the order given above. From
each participant all the data were recorded and orthographically transcribed
in English and Swahili.
For each question, the participants were encouraged to say as much as
possible. All the audio-recorded samples were orthographically transcribed
2.2. METHODS AND PROCEDURES
47
verbatim. The sparse number of intrusions from the other language was ignored. After transcription the samples were segmented into utterances. Each
utterance was considered a ‘sentence’ based on Hartmann and Stork’s (1972)
definition of a clause as a grammatical unit that includes, at the minimum, a
predicate and an explicit or implied subject and expresses a proposition.
2.2.4
Analysis
300 words is a reliable sample size for spontaneous speech analysis for languages
like English, Italian and Dutch (see Brookshire & Nicholas, 1994). However,
Swahili, unlike English, is a highly agglutinative language and much information that is expressed in single words in English is expressed by suffixes in
Swahili. Therefore, a comparison of samples of the same size would be inappropriate. A first analysis of both the NBD samples showed that for speech
rate and MLU the ratio of English and Swahili is around 3:2, meaning that the
information conveyed in 300 words in English is given in around 200 words of
Swahili. Therefore, 200 words of the Swahili samples were analyzed.
To determine whether speech which was characterized as ‘agrammatic’ for
English in bilingual participants by the SLTs was similar to agrammatic speech
of monolingual speakers of English, a comparison was made between the American English agrammatic data of eleven monolingual speakers from Thompson
et al. (2010) and the Kenyan English samples. The following variables were
analyzed:
• speech rate (number of words produced per minute)
• mean length of utterances (total number of words divided by the number
of utterances).
• noun to verb ratio
• percentage grammatical sentences
Subsequently, the English and Swahili samples were then compared on the
following variables:
• mean length of utterances and speech rate
• number and diversity of nouns and verbs and number of copulas and
(modal) auxiliaries
48 CHAPTER 2. CHARACTERISTICS OF SWAHILI-ENGLISH AGRAMMATISM
• percentage grammatical sentences and proportion of embedded / complex
sentences
Finally, for the analysis of verb inflection and time reference through verb
forms, we analyzed:
• number of verb inflections for tense and agreement on the lexical verbs
• time reference through verb inflection (number of verb forms referring
to the present and the past, including copulas, auxiliaries and modals,
taking both tense and aspect into account6 )
We ensured a balanced representation of all the questions by extracting an
equal number of words from every section (flood rescue, cookie theft, interview).
For statistical analysis, we used non-parametric tests (Mann-Whitney U test
was used for between-group comparisons) because of the small group sizes.
Transcription procedure and the inter-transcriber reliability
All collected spontaneous speech samples were orthographically transcribed
verbatim and then segmented into utterances using prosodic features as well as
syntactic structure to determine utterance boundaries, and analyzed for lexical, morphological, and structural measures. Minor utterances (e.g., ‘yes it is’,
‘no it isn’t’ for English, ‘sawa sawa’, ‘ndio’ in Swahili), voiced and unvoiced
starters, repetitions of words or sentence chunks, non-meaningful words, and
fillers or interjections were excluded. For analysis (300 words for English and
200 words for Swahili), the focus was on clauses that contained a verb: utterances containing verb, copula, modal, or auxiliary were analyzed. Initial
transcription and segmentation was done by a student of clinical linguistics,
a bilingual speaker of Swahili and English, who was trained on this method
of analysis. The transcriptions and segmentations were checked for reliability by a second transcriber, the first author (TA), also a bilingual speaker of
Swahili and English, and verified by the second author (RB) for English. The
same procedure was used for the analysis. The results of the two raters were
compared and the disagreements were resolved.
6 For
both languages, present tense-imperfective aspect (for English, for example, writes
and is writing) was taken as referring to the present and past tense-imperfective aspect,
present tense-perfect aspect or past tense-perfect aspect (for English: wrote, has written,
has been writing, was writing, respectively) was considered to be reference to the past.
2.3. RESULTS
2.3
2.3.1
49
Results
Comparison of the Kenyan English samples with
those of American English agrammatism
Since we had no test data that characterized Broca’s aphasia, agrammatism
in Kenyan English, we compared the English agrammatic data with the pretreatment data of eleven American agrammatic speakers from Thompson et al.
(2010). As can be seen from Table 2.2, the mean scores are very similar and so
are the ranges. The Kenyan English aphasic speakers talk slowly, in short and
simplified sentences which are often incomplete and / or ungrammatical. We,
therefore, consider these samples as typically agrammatic. This, in combination
with the well-preserved comprehension of single words, justifies the assumption
these agrammatic speakers suffer from Broca’s aphasia, at least in English. In
the next sections, we will compare their data for both English and Swahili.
Table 2.2: The means and ranges compared for the Kenyan English agrammatic samples and
the American narrative speech data of Thompson et al. (2010).
Kenyan English agrammatic
Mean
Range
MLU
Words / minute
Noun verb ratio
% Grammatical
sentences
2.3.2
American English agrammatic
Mean
Range
6.02
51.5
1.52
2.9-7.7
14-70
0.82-1.63
5.18
46.37
1.34
2.3-7.2
11-83
0.76-2.10
49.5
13-65
46.1
22-75
Comparison of the English and Swahili samples of
the agrammatic and non-brain-damaged speakers
Mean Length of Utterances and Speech Rate
The results reveal a serious fluency reduction in the agrammatic speakers. Their
speech rate is low and the utterance length is considerably reduced (see Table
2.3). The differences between the NBD and agrammatic group were significant
for both MLU (for English: z = -3.37, p< .001, for Swahili: z = -3.37, p< .001)
and speech rate (for English: z = -3.37, p < .001, for Swahili: z = -3.37, p <
.001). In fact, for both variables and in both languages, each of the agrammatic
50 CHAPTER 2. CHARACTERISTICS OF SWAHILI-ENGLISH AGRAMMATISM
speakers scores outside the normal range. The data reveal that the agrammatic
speakers performed very similar in both languages: their MLU was 60.4% of
that of NBDs in both English and Swahili and their speech rate was reduced
with 61.1% in English and 58.5% in Swahili. The corresponding patterns evident in the two languages confirm that the brain-damaged participants had a
quantitatively and qualitatively similar aphasia in both languages.
Table 2.3: The comparison of the Mean Length of Utterances (MLU) and speech rate (words
per minute).
MLU
LA
MM
EA
HJ
JK
SW
NBDs’ range
English
Speech Rate
7.692
6.818
2.941
5.172
6.977
6.522
8.11-10.71
70
63
14
46
61
55
119-140
MLU
Swahili
Speech Rate
4.255
4.082
2.778
3.636
4.348
3.846
5.41-7.14
65
40
9
50
56
60
75-100
Nouns, Verbs, Copulas and Auxiliaries
The analysis of the noun and verb production showed that the agrammatic
speakers fell within the normal range in both English and Swahili with only
a few exceptions. There were no significant differences between the groups:
noun tokens (for English: z = -.33, p >.05, for Swahili: z =-.56, p > .05); noun
diversity (for English: z = -.7, p >.05, for Swahili: z = -.37, p > .05); verb
tokens (for English: z = -.28, p >.05, for Swahili: z = -.56, p > .05); verb
diversity (for English: z = -.23, p >.05, for Swahili: z = -.14, p > .05); copulas
(for English: z = -.52, p >.05, for Swahili: z =-.66, p > .05); and auxiliaries
(for English: z = -.09, p >.05, for Swahili: z =-.9, p > .05). Some individual
agrammatic speakers showed behavior outside the normal range: EA overused
nouns in the English sample and produced a reduced number of copulas and
auxiliaries in both English and Swahili. MM’s use of auxiliaries was outside
the normal range in Swahili. Overall, the production of nouns, verbs, copulas
and auxiliaries was quite normal, however.
It can also been seen from Table 2.4 that the number of nouns and verbs
is very similar in English and Swahili and comparable between the two groups
2.3. RESULTS
51
(except that the mean number of nouns in the agrammatic group is a bit higher
for the agrammatic speakers when speaking English, due to the large number
of nouns produced by EA). This is interesting, because the English sample
size was 300 words and the Swahili sample size 200 words. It shows that, as
expected, in English many more function words are used than in Swahili, the
latter being a far more agglutinative language. This not only holds for the
NBDs, but also for the agrammatic speakers, who are supposed to be poor in
the production of function words.
Table 2.4: The comparison of noun and verb production between the agrammatic and nonbrain-damaged speakers in English and Swahili.
Languages
English
Swahili
Noun-tokens
Noun-types
Verb-tokens
Verb-types
Copulas
Auxiliaries
Noun-tokens
Noun-types
Verb-tokens
Verb-types
Copulas
Auxiliaries
LA
MM
37
26
45
28
10
16
35
23
44
28
7
11
57
31
35
20
11
19
58
20
33
15
9
3
Agrammatic speakers
EA HJ JK SW
99
45
56
32
0
3
48
26
26
18
2
0
54
27
47
25
9
11
41
23
57
38
1
10
43
26
43
28
12
20
41
24
53
32
8
9
47
26
32
22
21
22
32
16
34
20
21
8
mean
NBD
range mean
56.2
30.2
43
25.8
10.5
15.2
42.5
22
41.2
25.2
8
6.8
28-63
16-45
31-51
20-32
5-18
8-32
27-58
11-32
23-49
18-34
3-14
5-14
47.6
28.4
41.8
26.3
9.9
16.4
44.8
22.7
38.5
25.2
8.6
9.4
Grammaticality and syntactic complexity
Analysis of the grammaticality and complexity of the produced sentences revealed that all the agrammatic speakers produced a significantly larger proportion of ungrammatical sentences (for English: z = -3.37, p <.001, for Swahili: z
= -3.37, p < .001) and a significantly smaller proportion of embedded sentences
(for English: z = -3.37, p <.001, for Swahili: z = -3.37, p < .001) than the NBDs
in both languages (see Table 2.5). Again, the data in English and Swahili are
very similar: the agrammatic speakers produce 10 times as many ungrammatical sentences in English and 8.6 times as many ungrammatical sentences in
Swahili than the NBDs. The NBDs produce 4.5 times as many embeddings in
English and 4.8 times as many in Swahili than the agrammatic speakers.
The ungrammatical sentences produced by the agrammatic speakers in both
52 CHAPTER 2. CHARACTERISTICS OF SWAHILI-ENGLISH AGRAMMATISM
English and Swahili were mainly incomplete structures (missing internal arguments; frequent omissions of free morphemes such as articles, prepositions,
determiners; substitutions of grammatical morphemes, such as inflections, leading to tense and agreement errors). Such frequent omission of elements within
a sentence, coupled with limited use of embeddings largely account for the
reduced length of utterances as mentioned above.
Table 2.5: Proportions of ungrammatical and embedded sentences of the agrammatic and
non-brain-damaged speakers in English and Swahili
Participants
LA
MM
EA
HJ
JK
SW
Mean
NBD
2.3.3
mean
Range
English
Ungrammatical Embeddings
sentences
18 (46%)
17 (39%)
89 (87%)
32 (55%)
15 (35%)
19 (41%)
31.7 (51%)
1.58 (5.1%)
0%-13%
7 (18%)
6 (14%)
0 (0%)
2 (3%)
4 (9%)
4 (9%)
3.8 (8%)
10.83 (36%)
27%-46%
Swahili
Ungrammatical Embeddings
sentences
15 (32%)
16 (36%)
66 (92%)
20 (36%)
14 (31%)
17 (35%)
24.2 (44%)
1.83 (5.5%)
0%-14%
5 (11%)
3 (7%)
0 (0%)
1 (2%)
4 (9%)
4 (8%)
2.8(6%)
8.75 (29%)
20%-52%
Verb inflection and time reference through verb
forms
Verb Inflections on Lexical Verbs
As shown above, the number of lexical verbs produced by the agrammatic
speakers was similar to that of the NBDs in both languages. However, in
English the agrammatic speakers produce a larger proportion of these verbs
as an infinitive and gerund than the NBDs (see Table 2.6). 89% of the lexical
verbs produced by the agrammatic speakers were in the infinitive or gerund (ing) form, compared to 74% in the NBD population (z = 3.32, p < 0.0001). For
Swahili, a similar comparison cannot be made. Unlike in English, uninflected
verb forms in Swahili do not exist. Nonfinite verb forms, that is, verb forms
that are not marked for tense and agreement, also bear inflection. These are
the infinitives and the consecutive forms, marked with ku- and ka-, respectively.
The agrammatic speakers use as many of these non-finite inflected lexical verbs
2.3. RESULTS
53
as the NBDs (z = 1.55; p > 0.05).
Table 2.6: The proportions of verb inflections on lexical verbs in English and Swahili produced by agrammatic and non-brain-damaged speakers.
English verb inflections:
Tense
Agreement
Infinitives &
inflections:
inflections:
v+ing
verb
-ed(irr)
-s
forms
LA
MM
EA
HJ
JK
SW
Mean
NBD:
Mean
Range
Swahili verb inflections:
Tense
Agreement
Infinitives &
inflections
inflections
Consecutive
Markers
-li, -na, -a
-ni, -a, -wa
ku-, ka-
4 (4)
1 (2)
1 (2)
3 (4)
5 (2)
4 (1)
3 (2.5)
0
2
0
2
1
1
1
41
32
53
42
37
27
38.7
26
13
0
15
28
20
17
29
13
1
42
40
31
26
17
12
1
31
22
15
16.3
8.8 (6.1)
6-14(>5)
1.83
1-5
30.9
23-41
25.83
17-42
29.0
17-43
10.50
4-17
(Irr = irregular verbs)
In English lexical verbs, only the third person singular, present tense is
inflected for agreement (-s) and only the past tense is marked on the verb
(-ed). In the NBD samples, 4.5% of the lexical verbs are inflected for the
3rd person singular, comparable to the percentage in the agrammatic speakers
(z = -1.36, p > 0.05). However, the agrammatic speakers used significantly
fewer tense markers in English than the NBDs (7.4% vs 20.95%; z = -3.32, p <
0.001). In Swahili, all finite verbs are bearing markers for agreement and tense.
Therefore, in Swahili the agrammatic speakers (and the NBDs) produce many
more verbs inflected for tense and agreement, but the pattern is the same: the
agrammatic speakers use a normal percentage of agreement markers (z = -0.98,
p > 0.05), but the use of tense markers is significantly reduced (z = -2.39, p <
0.02).
In summary, when agrammatic speakers produce lexical verbs in the English
condition, they overuse forms that are not inflected for tense and agreement
(infinitives and gerunds). The number of finite verbs inflected for third person
singular, present tense is normal, meaning that agreement inflection, as far
as measurable in English, is intact, although there were only a few instances
of agreement inflection in the data set. However, the overt tense marker in
English, -ed, in combination with the irregular past tense forms, is used with
a lower frequency than normal. In Swahili, uninflected forms of verbs do not
54 CHAPTER 2. CHARACTERISTICS OF SWAHILI-ENGLISH AGRAMMATISM
exist and are not produced when the agrammatic speakers produce Swahili.
The number of infinitives and consecutive forms is not statistically different
from normal. Just like when they are speaking English, agreement inflection is
intact, but tense inflection is produced less frequently than normal.
Time Reference through verb inflection
Tense and aspect inflections are used to refer to a time frame, that is, past,
present or future. Since the majority of tense inflections in both languages
and in both populations were to present and past, reference to the future was
ignored in the current analysis. Not only the tense and aspect inflections of
lexical verbs were tallied, but also copulas and auxiliaries.
Table 2.7: Production time reference through tense and aspect in English and Swahili by
agrammatic and non-brain-damaged speakers.
English time reference
Past
Present
(tense & aspect) (tense & aspect)
LA
MM
EA
HJ
JK
SW
Mean
NBD:
Mean
Range
Swahili time reference
Past
Present
(tense & aspect) (tense & aspect)
(-li- & -me-)
(na-, -a-)
19
6
6
18
10
16
12.5
27
36
26
25
30
24
28
6
14
0
12
13
5
8.3
26
12
0
10
23
15
14.3
24.5
20-29
15.8
10-21
18.3
16-30
11.9
8-19
As shown in table 2.7, both in English and in Swahili, the individual agrammatic speakers’ use of verb forms referring to the past was outside the normal
range and significantly lower than in the NBDs (for English: z = -3.37, p <.001,
for Swahili: z = -3.37, p < .001). This was not the case for verb forms referring
to the present. In fact there was a substantial overuse of present verb forms by
the agrammatic speakers in English (z = -3.37, p = <.001), but not in Swahili
(z = -.84, p > .05 ) compared to the NBDs. A further comparison of the use
of verb forms referring to the past and those referring to the present within
the agrammatic speakers group reveals a preference for verb forms referring to
the present over those referring to the past, a difference that is significant for
2.4. DISCUSSION
55
English (z = -2.88, p = <.01), but not for Swahili (z = -1.12, p = > .05).
2.4
Discussion
This section discusses three research questions outlined in section 1.5, namely
(1) Are there similarities or differences in the English speech production of
monolingual and bilingual aphasic speakers? (2) What are the features of
Swahili agrammatism? How comparable are they with the features of English
agrammatism? (3) What are the agrammatic speakers’ patterns of production of verb inflection for tense and time reference in Swahili and in English?
Are verb forms referring to the past impaired? The section will end with a
discussion on linguistic complexity and frequency.
2.4.1
Comparisons with American English data
The results of the analysis of the Kenyan-English samples were compared to
those provided by Thompson et al. (2010) to determine whether analysis of
spontaneous speech in languages for which aphasia tests are not available is
sufficient to identify agrammatism. The similarities were remarkable: the
Kenyan-English samples had the same speech rate, mean length of utterances,
noun-to-verb ratios and percentages of grammatical sentences as the American
English agrammatic samples of Thompson et al. (2010). This, in combination
with the good performance on the BDAE subtest for auditory word comprehension, shows that the spontaneous speech could be characterized as ‘agrammatic’
and that the agrammatic speakers could be classified as suffering from Broca’s
aphasia, at least in English, although no formal Kenyan tests are available.
Knowing that these aphasic individuals were agrammatic in English allowed us
to do additional analyses and to make comparisons with the Swahili samples,
to see whether the spontaneous speech in this language can also be qualified as
agrammatic.
2.4.2
Comparison of the English and Swahili samples
The analysis of Swahili agrammatic samples compared to those of NBDs shows
features that generally quantify agrammatism: reduced spontaneous speech
out; low speech rate; shorter utterances; limited use of embeddings in sentences;
and production of large proportions of ungrammatical sentences. For cross-
56 CHAPTER 2. CHARACTERISTICS OF SWAHILI-ENGLISH AGRAMMATISM
linguistic comparisons, we first compared the mean length of utterances (MLU)
and speech rate (words per minute). The results showed similar pattern in
Swahili and English: a considerable reduction in utterance length and the
delay in speech rate is similar in both languages.
Second, the use of nouns and verbs (including copulas and auxiliaries) is
very much alike in both languages. Somewhat surprisingly, the scores on these
variables are not different from normal. On the basis of the literature (e.g.,
Bastiaanse & Jonkers, 1998; Thompson et al., 1997) it was expected that the
agrammatic speakers would produce fewer lexical verbs and / or lexical verb
types, as well as fewer copulas and auxiliaries. However, this pattern was
not observed in our agrammatic speakers in either language. There are at
least two other studies that report the same results. Lorch (1990) studied verb
production in three highly inflectional languages (Hindi, Icelandic and Finnish)
and showed that agrammatic speakers’ production of verbs and verb-types was
not impaired in all speakers. More recently, a study by Crepaldi, Ingignoli,
Verga, Contardi, Semenza, and Luzzatti, (2011) did not report a noun-verb
dissociation in Italian agrammatic speech. However, looking at the individual
data of the current study, we see that EA, who was the most severely aphasic,
had difficulties producing both copulas and auxiliaries in the two languages.
MM had difficulties with auxiliaries only in Swahili. Our interpretation of
the current data is that the agrammatic speakers in this study may not have
specific retrieval problems for lexical verbs, at least not in their spontaneous
speech. Their ability to retrieve nouns, lexical verbs and other categories of
verbs appears to be intact. Interesting is the finding that even though lexical
verbs and other verb categories are retrieved normally by these agrammatic
speakers, the proper use of the retrieved verbs in sentences is generally impaired
leading to higher proportions of ungrammatical sentences. The agrammatic
speakers often omitted complements (obligatory and implicit arguments).
Finally, as per our expectation, the agrammatic speakers produce more
ungrammatical sentences and fewer embedded sentences than NBDs in both
languages. Again, there is a similar pattern in Swahili and in English. The
agrammatic speakers’ ability to produce grammatically correct sentences that
are typically longer and/or complex (with embeddings) is clearly disrupted,
confirming the results of previous studies on agrammatism (see section 2.1.3).
In sum, the agrammatic symptoms in both languages are very similar on
variables that were not expected to yield different results in the two different
2.4. DISCUSSION
57
languages: reduced speech rate, short utterances, high proportion of ungrammatical sentences, and fewer embedded sentences. Unexpectedly, the production of verbs is well-preserved in both languages, which is not common in
agrammatic spontaneous speech. Still, the noun-verb ratio of our English samples is comparable to those of Thompson et al. (2010) for American English
agrammatic speech.
2.4.3
Verb inflection and time reference
The final question addressed the production of verb inflection. Two subquestions were raised. First, whether there would be differences in the use of
verb inflections in these typologically different languages and second whether
there was a selective disorder for verb forms referring to the past. With regard
to the first sub-question, several theories were addressed in the Introduction.
In spontaneous speech it is hard to point to obvious errors, but it was clear that
those verb forms that were produced were usually correct, in both languages.
Thus, it is not the case that more errors are made in Swahili than in English.
In English, the agrammatic speakers overused the infinitive and gerund forms
of lexical verbs. In Swahili, the infinitive and narrative markers (ku- and ka-)
were produced slightly more often than normal, although the difference is not
significant. When the finite verbs are compared, we see that in both languages
agreement inflection is normal, but the production of tense inflection is compromised, although less in Swahili than in English (English 35% of the normal
number of Tense inflections, in Swahili 57%). This is in line with the findings
of Knoph (2011) and Alexiadou and Stavrakaki (2006) who also reported that
inflection of the morphologically most complex language is best preserved. It
also supports the findings of our earlier study in which the English-Swahili
agrammatic speakers’ production of past tense forms were impaired in English
but not in Swahili (Abuom et al. 2011). These authors explained this by the
assumption that inflection for Tense is much more anchored in the Swahili language system, with its very rich and informative paradigm, than in English,
in which the lexical verb is not even marked for two time frames (present and
future). In the final section we will return to the issue why there is a slightly
better performance on Tense in Swahili than in English, regardless of the morphological complexity of the two languages.
Grodzinsky’s (1991; 1999) and Paradis’ (1995) claim that omission of grammatical inflections occurs in languages that allow bare forms. They also claim
58 CHAPTER 2. CHARACTERISTICS OF SWAHILI-ENGLISH AGRAMMATISM
that substitutions will be produced in languages where omissions result in nonwords. Both claims are supported by our data. Speaking in English results in
an overuse of infinitives, whereas speaking in Swahili results in a more than
normal number of verbs with ku- and ka- markers. However, in English gerunds
are also overused and these forms are inflected (-ing). Thus, the results may
also be explained in a different way: in both languages the agrammatic speakers show a preference for non-finite verbs, whether or not they are inflected.
This is more in line with the idea of Fabbro (2001), who expects the same errors in both languages. This seems, indeed, to be the case: in both languages,
the agrammatic speakers refrain to non-finite verbs, that is, verbs that are not
inflected for tense and agreement.
Why would agrammatic speakers use these forms? Obviously, it is not because they have problems with agreement markers, as their use of this affix
is normal. However, inflecting a verb for Tense is difficult for them. They
produced fewer tense inflections in both languages compared to the non-brain
damaged speakers. The data suggest that this is not because they have problems with tense in general. The use of verbs in the present tense is normal
in both languages. However, if we take both tense and aspect into account,
and make a division between verb forms that refer to the present and verb
forms that refer to the past, the real underlying deficit appears, a deficit that
manifests itself in both languages. It is reference to the past through verb
inflection that is impaired: in both languages the agrammatic speakers produce significantly fewer verb forms that refer to the past; and in English this is
compensated by an overproduction of verb forms referring to the present. This
selective deficit for verb forms referring to the past has been reported before
for monolingual agrammatic speakers in studies: spontaneous speech (Simonsen & Lind, 2002; Stravakaki & Kouvava (2003); conversation analysis (Beeke
et al., 2003a); and in experimental study (see Bastiaanse et al., 2011, for an
overview). These results are in line with the prediction made by the PADILIH
(Bastiaanse et al. 2011). Reference to the past is discourse linked, whereas
reference to the present is bound within the sentence.
2.4.4
Linguistic complexity and frequency
It has often been suggested that agrammatic (or telegraphic) speech is due to
decreased processing abilities. The idea is that what is more complex requires
more resources, hence, more difficult to produce or comprehend for individuals
2.4. DISCUSSION
59
with agrammatic aphasia. Although this sounds reasonable, the crucial question is what is complex and what is simple. According to some, complexity
is based on frequency: highly frequent constructions (such as active sentences
in English) require less processing load than infrequent constructions (such as
passives), and are therefore easier to process for agrammatic individuals. Recently, Bastiaanse, Bouma and Postma (2009) showed that frequency is not
the key factor in agrammatism, at least not in production: Dutch agrammatic
speakers have less problems when asked to complete (a less frequent) embedded
clause than (a high frequent) matrix clause. This can be explained in terms
of linguistic complexity, but not in terms of frequency, although both factors
often co-incide. Bastiaanse et al. (2009), therefore, suggest that the complexity
hierarchy should be defined in linguistic terms. Avrutin (2000; 2006) offers a
model how this works. With his competition model, he shows why certain linguistic categories (such as pronouns and which-questions) are harder to process
for agrammatic individuals than other categories (reflexives and who-questions,
respectively). The first category members require discourse linking that is processed by discourse syntax; the second are bound within the sentence and need
to be processed by narrow syntax. The critical point in his argumentation is
that discourse syntax requires more processing resources than narrow syntax
and, therefore, narrow syntax is used to process all these categories, resulting
in problems when elements are discourse-linked, like verb forms that refer to
the past.
However, the present data of bilingual agrammatic speakers present problems to this sort of processing model. It is obvious that the Swahili verb inflection paradigm is more complex than the English paradigm, both intuitively
and from a linguistic point of view. Therefore, one expects the agrammatic
speakers to have more problems in Swahili, which, however, is not the case.
Just like in the study of Abuom et al. (2011), more problems arise with the
simple paradigm. It is hard to see how or why the Swahili verb inflection
paradigm requires less processing load than the English one. The theory raised
by Abuom et al. (2011), that verb inflection is more anchored in the Swahili
language system, may be on the right track, but it does not give an explanation
in terms of processing load. Another problem is that even if the verb inflections
are more anchored in the Swahili system, the selective problems with reference
to the past are similar as in English (though less severe). Goral (2011), however, suggests that it is not a matter of morphological complexity but rather
60 CHAPTER 2. CHARACTERISTICS OF SWAHILI-ENGLISH AGRAMMATISM
of regularity. She argues that the morphology of a language with complex but
regular morphology is likely to be better preserved than the morphology of a
language with simple but not completely regular morphology. This argument
has been substantiated by Bybee (2007) who associates regular morphology
with affixation and irregular morphology with internal stem change. Bybee
(2007) argues that affixation (regularity) is rather more ‘natural’ and highly
frequent in most languages, hence easier to process in general; whereas internal
stem change (irregularity) is rather less ‘natural’, lexically arbitrary and of low
type frequency, hence more difficult to master. Centeno and Anderson (2011)
demonstrate that individuals with linguistic limitations (such as agrammatic
speakers, children with SLI), in their oral expression, have a preference for highfrequency linguistic items over low frequency items in a language. This theory
partly explains high preference for present verb forms in both languages, as well
as the slightly better preserved Tense system in Swahili than in English regardless of the morphological complexity of the two languages. Swahili past Tense
has only one regular form marked as an infix on the verb paradigm, whereas
English past Tense has both regular and irregular forms. Furthermore, Swahili
verb morphology has high frequency of affixation compared to English, which
combines a few instances of affixations and internal stem changes.
In sum, the current data and the discussion thereof do not offer an answer
to the question on the underlying deficit. It rather challenges the theories that
pose that it is a matter of processing load. We do not dispute that agrammatism
is a processing rather than a representational deficit. However, we do think that
more data and more refined experiments are needed to generate a theory that
can explain the problems of agrammatic speakers in terms of complexity in
relation to the effects of diminished processing abilities due to brain damage.
The present study demonstrates that studies in bilingual populations can be
very helpful, if not in solving the problem, then at least in revealing the weak
points.
CHAPTER
3
Production and Comprehension of Reference of Time in
Swahili-English bilingual agrammatic speakers
Abstract
Background: Several studies on time reference show that monolingual agrammatic speakers have difficulty producing and/or comprehending verb forms
referring to past events or actions. The PAst Discourse LInking Hypothesis
(PADILIH) has been formulated to account for this phenomenon (Bastiaanse,
Bamyaci, Hsu, Lee and Yarbay Duman, 2011). In the current study on bilingual aphasia, we examine whether time reference problems, especially reference
to the past, extend to both languages of bilinguals with agrammatic aphasia.
The two languages, Swahili and English, have different verb morphology for
expressing reference of time.
Aims: The current study tested the production and comprehension of reference of time through verb morphology in two languages of Swahili-English
bilingual agrammatic speakers.
This study has been published as:
Abuom, T. & Bastiaanse, R. (2013). Production and Comprehension of Reference of
Time in Swahili-English bilingual agrammatic speakers. Aphasiology 27, 157-177.
61
62
CHAPTER 3. TIME REFERENCE PRODUCTION AND COMPREHENSION
Methods & procedures: Thirteen agrammatic speakers and thirteen nonbrain-damaged individuals were tested using an adaptation of the Test for
Assessing Reference of Time (TART; Bastiaanse, Jonkers, & Thompson, 2008;
Swahili version: Abuom & Bastiaanse, 2010). Reference to the past, present
and future conditions were examined through a sentence-completion and a
picture-sentence matching task.
Outcomes & Results: While the non-brain-damaged participants performed
at ceiling in both languages, the agrammatic individuals’ performance showed a
selective deficit of reference to the past on both comprehension and production
tasks. A similar pattern was observed in the two languages in spite of the
structural differences.
Conclusions: The PAst Discourse LInking Hypothesis (PADILIH) was supported by these results. Furthermore, it has been revealed that time reference
deficits extend to both tested languages of bilingual speakers with agrammatic
aphasia regardless of the structure of languages mastered pre-morbidly. The
implications of these findings for the theories of bilingual agrammatism are
discussed.
3.1
Introduction
In daily life communication, it is often easy and rather effortless not only to talk
about, but also to understand, events or actions that: happened in the past, is
happening at the present, or will happen in the future. The use of verb inflections to communicate time reference is generally not a problem for most people.
However, there is evidence that this may not be the case with brain damaged
individuals suffering aphasia. Recent cross-linguistic studies on time reference
indicate that individuals with agrammatic aphasia have problems with verb inflections for reference to the past time-frame (e.g. Stavrakaki & Kouvava, 2003
and Nanousi, Masterson, Druks and Atkinson (2006) for Greek; Bastiaanse,
2008; Jonkers & de Bruin, 2009 for Dutch; Yarbay Duman & Bastiaanse, 2009
for Turkish; Abuom, Obler, Bastiaanse (2011), Bastiaanse, Bamyaci, Hsu, Lee
and Yarbay Duman (2011) for English; Abuom & Bastiaanse (2012) for Swahili
and English). It is, however, not clear how these problems with time reference
are reflected in both languages spoken by a bilingual agrammatic individual.
This is particularly interesting when the languages have very different verb
inflection paradigms, as in this case, Swahili and English. The verb inflection
3.1. INTRODUCTION
63
paradigm of Swahili is very large, whereas it is relatively small in English.
The current study investigates the performance of pre-morbidly highly proficient Swahili-English bilingual agrammatic speakers on production and comprehension of time reference in both languages. The question is how time reference problems, especially reference to the past, are manifest in both production
and comprehension of the Swahili-English bilingual agrammatic speakers. The
study will determine whether the size of the verb inflection paradigm influences
the performance of the agrammatic speakers quantitatively and qualitatively,
and whether the language with a larger paradigm (Swahili) is more or less
impaired than the one with a smaller paradigm (English).
In the next sections we will first present a description of time reference morphology in Swahili; followed by an overview of the literature on time reference
problem among monolinguals and bilinguals with agrammatic aphasia. The
predictions for the current study will conclude the introduction section.
3.1.1
Time reference morphology in Swahili
Swahili, a Bantu language spoken mostly in Africa, including Kenya, has Subject - Verb - Object as the basic word order (Ashton, 1982). Kenya is a multilingual society with an average person speaking at least three languages. Swahili
and English are the two most dominant languages across the country, used
both as official and as national languages, but most Kenyans speak an extra
language from the 42 languages linguists refer to as “ethnic languages” (classified under four broad categories: Bantu; Nilotic; Indo-Aryan; and Cushitic
languages) at home as well. Swahili and English have the same status as second languages since both are acquired around the age of 4, after acquiring the
native language.
Swahili’s most distinguishing characteristic is its agglutinative aspect; and
of greatest interest to this study is the size of the verb structure consisting
of prefixes and suffixes. Time reference for Tense and Aspect in Swahili is
done through verb inflection as a prefix in the verb complex. The complete
structure of the Swahili verb paradigm is illustrated in (1). It is important to
note that the subject agreement (Sp), tense (T), root and the derivation (d)
are obligatory in every affirmative Swahili utterance.
The Tense system used for time reference in Swahili is given in examples
(1a-e).
64
CHAPTER 3. TIME REFERENCE PRODUCTION AND COMPREHENSION
(1)
Pre-prefix (Pp)7 + Subject prefix (Sp) + Tense prefix (T) + Object
prefix (Op) + ROOT + derivation (d) + Suffix (S)+ Post-suffix (Ps)8
(a)
LEO
[Wa + na + tak
+ a] ku + m + pig
+a
TODAY [Sp + T + ROOT + d] Pp + Op + ROOT + d
‘TODAY [they want] to hit him/her’.
(b)
JANA
A + li + m + pig
+a
YESTERDAY Sp + T + Op + ROOT + d
‘YESTERDAY she/her hit him/her’.
(c)
LEO
U + me + m + pig
+a
TODAY Sp + T + Op + ROOT + d
‘TODAY you have hit him/her’.
(d)
SASA Tu + na + pig
+a +n +a
NOW Sp + T + ROOT + d + S + Ps
‘NOW we are hitting each other’.
(e)
KESHO
Ha + tu + ta
TOMORROW Pp + Sp + T
+ m + pig
+a
+ Op + ROOT + d
‘TOMORROW we will not hit him/her’.
As illustrated in (1a-e), Swahili has three explicit morphological markers of
Tense: past, present and future. The infinitive (1a) is also marked in Swahili by
the prefix KU- attached either directly to the verb root as in ‘to hit’ (kupiga)
or attached to the object prefix with the verb root as in ‘to hit him/her’
(kumpiga). This prefix KU Corresponds to the English infinitive generally
signaled by the use of ‘to’ before the verb. The past Tense marker formed
by the insertion of the prefix -LI, as in (1b), refers to a past activity without
reference to a specific time. The prefix -LI corresponds to the simple past in
English (Verb + ed: he painted). The present perfect Tense inserted as a prefix
-ME- (1c) refers to a past activity which has relevance to the present time. The
prefix -ME- is comparable to the present perfect in English (has/have + Verb+
ed : he has painted). The present Tense -NA- describes actions taking place at
the present moment (1d) comparable to either the English present progressive
7 The
pre-prefix is a negation marker found in all negative sentences. It has, however, not
been included in the present test.
8 It is not possible for a verb to possess all these affixes at one and the same time.
3.1. INTRODUCTION
65
(Verb + ing: he is hitting him) or simple present (Verb + s: he hits him). The
future Tense marker -TA- describes events assumed to follow the present moment (1e), corresponding to reference to the future through periphrastic form
in English (will + infinitive: he will paint).
It is generally considered ungrammatical to omit Tense markers in any
Swahili utterance whether or not the temporal reference is clear from the discourse or any other sources (with the exception of imperative sentences such
as ‘Nenda nyumbani’, a translation equivalent of ‘go home’ in English). The
grammatical structure of time reference morphology for the two languages is
clearly different: Swahili has a large verb inflection paradigm that can function
as a complete sentence on its own; whereas, English has a rather small verb
paradigm that requires other sentence constituents.
In sum, verb morphology in Swahili appears complex due to its relatively
large number of affixes on the verb paradigm, but it is completely regular. Also,
time reference is simple: there are only three tenses expressed through affixes
which are inserted in the same position for every single verb. No irregular verbs
exist. In English, the finite verb itself is simpler than in Swahili, but there is
a wider variation in inflection for time reference, since it is inflected for both
tense and aspect. The inflection is done by both analytical verb forms (‘wrote’)
and periphrastic verb forms (‘has written’). Additionally, English has regular
and irregular verbs. This means that overall the Swahili finite verbs are more
complex, because Swahili is an agglutinative language where the finite verbs
incorporate more information, although inflection for time reference is simpler
than in English.
3.1.2
Time reference problem in monolinguals with
agrammatic aphasia
Most languages express time reference through tense and aspect. A number of
studies that have compared the processing of Tense and Agreement in individuals with agrammatic aphasia show that Tense inflections are more prone to impairment than Agreement inflections. Friedmann and Grodzinsky (1997) found
impaired tense inflection, but intact agreement inflection in Hebrew aphasic
speaker. They, as a result, proposed the so called Tree Pruning Hypothesis
(TPH), which attributes the difficulty with tense to its higher position in the
syntactic tree. Wenzlaff and Clahsen (2004) found similar results for German
aphasic speakers. However, they proposed the Tense Under-specification Hy-
66
CHAPTER 3. TIME REFERENCE PRODUCTION AND COMPREHENSION
pothesis (TUH), which relate the tense problem to the fact that tense carries
extra-sentential information. Burchert, Swaboda-Moll and De Bleser (2005),
however, found both tense and agreement can be difficult for German agrammatic speakers. They proposed the Tense and Agreement Hypothesis (TAUH),
arguing that both tense and agreement can be affected independently in agrammatic speakers. However, what these studies fail to show is: whether Aspect
is impaired as well; and whether past Tense inflections are impaired selectively
or not.
The findings by Stavrakaki and Kouvava (2003) and Nanousi, Masterson,
Druks and Atkinson (2006) for Greek; Bastiaanse (2008); Jonkers and de Bruin,
(2009), for Dutch; Yarbay Duman and Bastiaanse (2009), for Turkish; and Bastiaanse et al. (2011) for English, Chinese and Turkish, show a selective impairment of reference to the past through Tense and/or Aspect. Stavrakaki and
Kouvava (2003) analysed the production of Tense, Aspect and Agreement in
the spontaneous speech of two Greek agrammatic speakers and found that past
Tense was more difficult to produce than the present Tense. Furthermore, the
past Tense with the perfective aspect (‘’I wrote’) was more difficult to produce
than the past Tense with the imperfective aspect (‘I was writing’). However,
the production of subject-verb Agreement was relatively spared. Nanousi et
al. (2006) also reported impaired perfective aspect in a group of Greek agrammatic speakers. Bastiaanse (2008) used a sentence completion task to assess the
performance of a group of Dutch agrammatic speakers on production of time
reference through Tense (past Tense versus present Tense) and periphrastic
forms (non-finite participle versus infinitive). The results were in line with the
findings of Stavrakaki & Kouvava (2003): past Tense forms were more difficult to produce than the present Tense forms. Interestingly, however, for the
non-finite forms, the production of the participle (used, in combination with a
present tense auxiliary, to denote perfect aspect; and not marked for gender or
number) was more impaired than the production of the (uninflected: with no
tense or agreement) infinitive.
Yarbay Duman and Bastiaanse (2009) examined the performance of a group
of Turkish agrammatic speakers on the production of Tensed finite verbs and
participles referring to the past and the future through a pictured sentence
completion task. Their findings revealed past Tense/perfect aspect to be more
difficult than future Tense/imperfect aspect for the Turkish agrammatic speakers. In another study on time reference in Dutch agrammatic speakers, Jonkers
3.1. INTRODUCTION
67
& de Bruin (2009) tested both production and comprehension of the present
and the past Tenses in seven individuals with Broca’s aphasia and five individuals with Wernicke’s aphasia using a sentence-to picture matching task for
comprehension and a sentence completion task for production. Jonkers & de
Bruin (2009) observed that past Tense forms were more impaired than present
Tense forms in both production and comprehension. They noted, however, that
past Tense deficit was a general problem that affects Broca’s and Wernicke’s
aphasic individuals alike.
The results of these studies raised the question why reference to the past is
more difficult for agrammatic individuals. Bastiaanse et al. (2011) formulated
the PAst DIscourse LInking Hypothesis (PADILIH) which is based on the idea
of Zagona (2003) that when referring to a present event through Tense, speech
time and event time are the same and hence, are locally bound. When referring to the past through Tense an extra-sentential reference is made, because
speech time and the (earlier) event time are different. Therefore, discourse
linking is required. For reference to the future, Bastiaanse et al. (2011) suggest that the relationship is neither discourse-linked nor locally bound since the
event has not yet happened (see also Zagona, in press). Avrutin (2000; 2006),
based on findings from a number studies, suggests that the interpretation of
discourse-linked relationships is a problem for individuals with Broca’s aphasia. He distinguishes ‘narrow syntax’, that is, syntax processes that are taking
place within the sentence structure, and ‘discourse syntax’, that is, processing
syntactic information at the discourse level. According to Avrutin (2000; 2006)
more processing resources are required to establish relationships with discourse
syntax information than with narrow syntax.
Bastiaanse et al. (2011), in proposing the PADILIH, expanded Zagona’s
(2003) theory on tense and discourse linking to include not only past Tense,
but all verb forms referring to the past, including periphrastic verb forms and
verb forms in perfect aspect. The PADILIH, therefore, predicts that all verb
forms referring to a past or finished event, regardless of Tense, are discourse
linked and, therefore, require more processing resources, leading to more errors
by grammatically impaired individuals.
In a cross-linguistic study, Bastiaanse et al. (2011) tested the PADILIH.
Agrammatic speakers of Chinese, English, and Turkish were assessed on both
comprehension and production of time reference morphology (in three conditions: past, present and future) using the Test for Assessing Reference of Time
68
CHAPTER 3. TIME REFERENCE PRODUCTION AND COMPREHENSION
(TART; Bastiaanse, Jonkers, & Thompson, 2008). Their results were in line
with previous findings on time reference: both Turkish and English agrammatic
speakers showed a selective deficit with reference to the past through verb inflections in production and comprehension. The Chinese agrammatic speakers’
performance on comprehension was relatively similar to those of Turkish and
English. However, the Chinese agrammatic speakers’ performed poorly on production of all the three time-frames: reference to the past, present and the
future. The authors attribute the Chinese production results to a general difficulty with aspectual adverbs: time reference is expressed through aspectual
adverbs rather than verb inflections. These findings were taken as support
for the PADILIH, attributing the problem with reference to the past, through
tense and / or aspect, to impaired discourse linking in agrammatic aphasia.
What all these studies on Tense and time reference have in common is
that they have mainly investigated monolingual agrammatic speakers. In the
present study with bilingual agrammatic speakers, the performance in both
Swahili and English can be compared to evaluate the influence of the verb
inflection paradigm on the severity of the time reference deficit.
3.1.3
Time reference problems in bilinguals with
agrammatic aphasia
In the current study, we use the term ‘bilingual’ to include both bilingual and
multilingual persons who make use of two or more languages or dialects in
their everyday lives (Grosjean, 1994). Most bilingual aphasic individuals suffer
from the same type of aphasia in all their languages mastered pre-morbidly;
and the recovery pattern commonly observed is parallel (Fabbro, 1999, 2001;
Paradis, 2001; Miozzo, Costa, Hernandez & Rapp, 2010; Abutalebi, Cappa, &
Perani, 2005). Non-parallel recovery patterns have also been reported and are
usually attributed to differences in either the age of acquisition, frequency of
use or proficiency level between the languages mastered pre-morbidly (Albert
& Obler, 1978; Fabbro, 1999). In early balanced and proficient bilinguals,
languages acquired early are generally assumed to be represented in shared
processing regions (e.g., Miozzo et al., 2010; Abutalebi et al., 2005).
When it comes to time reference problems among bilingual aphasic speakers,
so far, only two studies have investigated the tense and time reference problem
in bilingual agrammatic speakers. In the first study, Abuom et al. (2011) tested
two Swahili-English bilingual agrammatic speakers on production of reference
3.1. INTRODUCTION
69
to the past and the future, using a sentence completion task. The English
data confirmed the findings of the previous studies on Tense and reference to
the past. However, reference to both the future and the past was intact for
Swahili in both agrammatic speakers. For the second study, Abuom and Bastiaanse (2012) analysed the use of verb inflections for tense and time reference
to the past and to the present in the spontaneous speech of six Swahili-English
agrammatic speakers. The results showed that the use of verb inflections for
reference to the present was normal in their spontaneous speech, but the number of verb forms referring to the past was significantly lower than normal.
However, overall, the use of verb inflections was better preserved in Swahili
than in English.
While the results of both studies on bilingual Swahili-English agrammatic
speakers concur with respect to the difficulty with producing reference to the
past in English, it is not yet clear whether Swahili is similarly affected. Furthermore, the comprehension of time reference in Swahili-English agrammatic
speakers has not been investigated. Therefore, it is unclear whether the predictions of the PADILIH apply similarly to the two languages of bilingual agrammatic speakers.
3.1.4
The current study
The current study examined the production and comprehension of time reference to the past, the present and the future in the two languages, using the
Test for Assessing Reference of Time (TART: Bastiaanse et al., 2008; bilingual
English-Swahili version: Abuom & Bastiaanse, 2010). We assume that balanced bilinguals who acquired their languages from an early age use a shared
grammatical device (Miozzo et al., 2010; Abutalebi et al., 2005). The key
research questions this study addressed were as follows:
(1) Is production of time reference to the past through verb inflection impaired in both languages of a bilingual?
(2) Is comprehension of time reference to the past through verb inflection
impaired in both languages of a bilingual?
(3) Is reference to the past similarly impaired in both Swahili and English?
According to PADILIH: (1) the production of time reference to the past
through verb inflection is impaired, whereas, reference to the present and fu-
70
CHAPTER 3. TIME REFERENCE PRODUCTION AND COMPREHENSION
ture are relatively spared; (2) the comprehension of time reference to the past
through verb inflection is impaired, whereas, reference to the present and the
future is relatively intact; (3) the impairment is language independent, hence,
both Swahili and English will be impaired similarly. However, according to
Bates, Friederici and Wulfeck (1987), in a language with a more complex inflectional paradigm, the cue cost is higher to produce the grammatical morphemes. This predicts that the bilingual agrammatic speakers will make more
errors in Swahili, where the verb inflection paradigm is larger (more complex).
However, Bates, Wulfeck and MacWhinney (1991) introduce the notion of cue
validity: inflectional markers that are more informative are better preserved
than inflectional markers that are less informative. With respect to the present
study, this theory predicts that past, present and future morphology will be
equally affected, since all three are used for reference to a time frame. Also,
cue validity is the same in English and Swahili. In sum: the cue cost in Swahili
is higher, so more errors are expected in Swahili; the cue validity in the two
languages is the same, so no differences are expected. Another interesting idea
was expressed by Goral (2011). She assumes that in bilingual agrammatic
aphasia, regular paradigms are better preserved than paradigms with irregular members. Goral (2011) thus expects Swahili with its fully regular, though
larger (complex) paradigm to be better preserved than English with its smaller
(simple) paradigm for reference to the past, that nevertheless contains three
different regular (-t, -d, -ed) allophones and irregular forms.
3.2
3.2.1
Method
Participants
There were a total of 26 participants in this study: 13 Swahili-English bilingual agrammatic speakers from Aga Khan University hospital Nairobi-Kenya
and 13 non-brain-damaged speakers (NBDs) matched in age, gender, native
language and education level to agrammatic speakers. All participants were
aged between 20 and 49 years, with over 12 years of education, and none had
any history of neurological, hearing or vision problems.
The agrammatic speakers had all suffered from single stroke with the exception of one, EA, who had left hemisphere brain damage due to a car accident.
They were early balanced bilinguals, equally proficient in English and Swahili
3.2. METHOD
71
pre-morbidly; any Kenyan adult with over 12 years of uninterrupted education
is generally expected to be equally highly proficient in both Swahili and English. The demographic details of the agrammatic participants are shown in
the Table 3.1.
Table 3.1: Demographic details and the results on the test for auditory comprehension of
words (on an adapted version of the BDAE-test in Swahili and English) of the
agrammatic speakers
Agrammatic
participants
SW
HJ
LA
MM
JK
EA
PN
JA
MW
VK
HS
JN
SS
Mean
Age
(years)
Gender
Handedness
Education
(years)
Years post
stroke/
head trauma
Native
language
Swahili
BDAEsubtest
English
BDAEsubtest
20
45
43
47
49
42
36
46
50
25
64
50
30
42.1
M
F
F
F
M
M
F
M
F
F
M
F
F
R
R
R
R
R
R
R
R
R
R
R
R
R
12
14
16
16
17
16
14
16
16
16
16
13
12
14.9
2
10
1
10
1
17
1
1
1.5
2
1
10
17
4.4
Bantu
Nilotic
Bantu
Nilotic
Bantu
Nilotic
Bantu
Bantu
Bantu
Bantu
Indo-Aryan
Bantu
Indo-Aryan
98.6%
100%
100%
100%
100%
100%
100%
100%
98.6%
100%
99%
100%
100%
99.7%
99%
100%
100%
100%
100%
99%
100%
100%
100%
98.6%
98.6%
100%
99%
99.5%
Their spontaneous speech was judged to be telegraphic with reduced speech
rate in both languages by a practicing speech therapist, and further confirmed
by the experimenter based on the criteria of Menn and Obler (1990)9 . However, due to lack of most relevant standardized tests for establishing the aphasia
syndrome in Kenya, we administered an adapted version of a sub-test from the
Boston Diagnostic Aphasia Examination (Goodglass & Kaplan, 1972) to ensure
their good comprehension abilities. They all had good comprehension in both
languages on the subtask for auditory comprehension of single words (nouns,
verbs, colors, shapes, letters, and numbers) from the Boston Diagnostic Aphasia Examination. Some pictures were substituted due to cultural differences,
for instance, a hammock was changed to a swing since no Swahili word exists.
Unfortunately, there is no information as to the possible extent of cognitive
damage in agrammatic participants. The agrammatic speakers’ scores on the
9 There
was spontaneous speech available of 6 of the patients, who also participated in
Abuom & Bastiaanse, 2012. Their speech was characterized by significantly (1) lower
speech rate; (2) shorter sentences; (3) fewer grammatical sentences; (4) fewer embeddings
in both Swahili and English.
72
CHAPTER 3. TIME REFERENCE PRODUCTION AND COMPREHENSION
BDAE subtest for auditory word comprehension are included in Table 3.1.
3.2.2
Materials and procedure
The African version (an adaptation for English and Swahili) of the Test for Assessing Reference of Time (TART: Abuom & Bastiaanse, 2010) was used. The
TART was developed for cross-linguistic investigation of comprehension and
production of reference of time and it has been used in several other languages
including: Dutch, English, Indonesian, Chinese, and Turkish. The test has two
sections with pictures of 20 verbs depicting actions in three time-frames: the
present (an on-going action), the past (a completed action) and the future (an
action about to start).
The production section consists of a sentence-completion paradigm with
prompting to elicit the intended verb forms. There are 20 items for each of
the three conditions: the simple past, the present continuous, and the future.
The following forms were elicited in the two languages: simple past (an infix
-li- for Swahili, and a suffix -ed for English); present continuous (an infix -nafor Swahili, and is + V -ing for English); future (an infix -ta- for Swahili, and
will + infinitive for English). The participants were presented with a pair of
pictures of contrasting actions in a particular time-frame (past, present and
future; see Figure 3.1 and the examples in 2a-c below) with the same object.
The infinitive form of the verb was printed above the pictures on the same
page (e.g. ‘write’ and ‘read’). The experimenter constructed a sentence for the
picture on the left using the appropriate temporal adverb with the correct form
of the verb. The participant was expected to complete the second sentence for
the other picture using the right form of verb after the experimenter has given
the temporal adverb and the subject (See example 2a-c for eliciting: present
continuous, past and future tenses in Swahili and English). Samples of pictures
for the production task are given in Figure 3.1a-c.
3.2. METHOD
73
(a)
WRITE
READ
(b)
POUR
DRINK
(c)
PEEL
EAT
Figure 3.1: Samples of the pictures used for production task: a) to elicit time reference to
the present; b) to elicit time reference to the past; c) to elicit time reference to
the future.
74
CHAPTER 3. TIME REFERENCE PRODUCTION AND COMPREHENSION
(2)
(a)
Examiner:
Sasa huyu
Now this
mwanamme
man
mwanamme a-na-andika
barua.
man
he-Present-write a letter.
...
...
Sasa huyu
Now this
‘Now this man is writing a letter. Now this man...’
Participant:
a-na-soma
barua
he-Present-read a letter
‘is reading a letter’.
(b)
Examiner:
Hapo-mbeleni
Previously
Hapo-mbeleni
Previously
huyu
this
huyu
this
mwanamme a-li-mwaga
maziwa.
man
he-Past-pour milk.
mwanamme ...
man...
‘Previously this man poured milk. Previously this man...’
Participant:
a-li-kunywa
maziwa
he-Past-drink milk
‘drunk milk’.
(c)
Examiner:
Hivi-punde
Soon
Hivi-punde
Soon
huyu
this
huyu
this
mwanamme
man
mwanamme
man
a-ta-menya
chungwa.
he-Future-peel orange.
...
...
‘Soon this man will peel an orange. Soon this man ...’
Participant:
a-ta-kula
chungwa
he-Future-eat orange
‘will eat an orange’.
The comprehension section consists of a spoken-sentence-to-picture-matching
3.2. METHOD
75
Figure 3.2: A sample of the pictures used for comprehension task
task. The pictures of 20 verbs depicting actions in three time frames from production task were also used in comprehension task. Constructions in three
time-frames (the simple past, the present continuous, and the future) were
used with each time frame consisting of 20 items. A pair of pictures was presented to the participants and a sentence with the target inflected form of the
verb was read aloud by the experimenter. The participants chose a picture
from the given pair that corresponds to the sentence read by the experimenter
(see example 3). The pictures depict actions in two contrasting time-frames
(see Figure 3.2).
(3)
Experimenter:
Mwanamme a-na-kula
chungwa
Man
he-Present-eat an orange
‘The man is eating an orange’
The TART has been translated into more than 15 languages, and the same
verbs are used for each language. Therefore, there were verbs with regular
(n=13) as well as irregular (n=7) past tense included in the English version.
The tests in each of the languages were administered on two different days
with an interval of two weeks for each of the agrammatic speakers. The order
of the tests was varied for each participant: either English first, followed by
Swahili or vice versa, but all participants were tested on production first before
76
CHAPTER 3. TIME REFERENCE PRODUCTION AND COMPREHENSION
comprehension in each language. The tests were conducted in a speech therapy
room at the Aga Khan University Hospital in Nairobi, Kenya. Each test session
began with six practice items to ensure the participants understood the task
before starting the test. The participants were corrected and given feedback
during the practice. No further feedback was given once the test was begun.
Each test session of the agrammatic speakers lasted one and half hours, with
a break.
3.2.3
Analysis
The 13 non-brain-damaged Swahili-English bilingual speakers, matched in age,
gender, native language and education level to the agrammatic speakers performed at ceiling on the two tests for both languages. We therefore assume
that all errors made by the agrammatic speakers are a result of their aphasia.
The agrammatic speakers’ data were analysed both quantitatively and qualitatively. For quantitative analysis, the number of both the correct and incorrect
responses produced, and the number of correctly identified pictures, by each
participant were tallied. Self-corrections were permitted during the test and the
final response was scored. Produced responses were considered correct when
the correct form of verb inflection was produced for the three time-frames in
Swahili (-li for simple past, -na for present continuous, and -ta for future) and
English (-ed for simple past, -ing for present continuous, and will + infinitive
for future). Omission of the object was ignored. For the qualitative analysis,
the three most frequent error types were distinguished in the production task:
substitution (e.g. ‘anakula’‘he is eating’ instead of ‘alikula’‘he ate’), omission
(e.g. ‘*sukuma toroli’‘pull the trolley’ instead of ‘alisukuma toroli’‘he pulled
the trolley’), and other errors (e.g. ‘*he sweeped the floor’ instead of ‘he swept
the floor’). For statistical analysis, we used repeated measures ANOVA (for
main effect of language, sub-test and time reference); t- tests (for differences
between the time-frames within each language, and between the two languages)
and correlations (for relationship in performance within and between the two
languages)
3.3. RESULTS
3.3
3.3.1
77
Results
Overall analysis:
A repeated measures analysis of variance was performed to investigate main
effects of language (English and Swahili), sub-test (production and comprehension) and time reference (past, present and future) on agrammatic performance.
There was a statistically significant effect for language: F (1, 12) = 19.340, p
= .001; Swahili was better preserved than English. There was also statistically
significant effect for Sub-test: F (1, 12) = 7.256, p = .020; production was
worse than comprehension in both languages, which is to be expected, since
there is a 50% chance level for the comprehension test. Furthermore, there was
a statistically significant main effect for time reference: F (2, 12) = 48.230, p
= .000; reference to the past was worse than reference to both the present and
the future in the two languages.
3.3.2
Production in English and Swahili
The production results are presented in Table 3.2.
Table 3.2: The comparison of agrammatic speakers’ scores on production of reference of time
in Swahili and English.
SW
HJ
LA
MM
JK
EA
PN
JA
MW
VK
HS
JN
SS
mean
Swahili Production
Past Present Future
English Production
Past Present Future
12
19
20
20
20
11
17
19
14
14
17
15
16
16.46
9
4
17
15
18
5
5
11
7
9
9
6
11
9.69
20
18
19
20
19
15
20
20
20
19
20
20
20
19.23
19
20
20
20
20
14
20
20
20
20
20
20
19
19.38
20
20
20
20
20
18
20
20
20
20
20
20
20
19.85
20
20
20
20
20
20
20
20
20
20
19
19
20
19.85
78
CHAPTER 3. TIME REFERENCE PRODUCTION AND COMPREHENSION
On the English version of the test, the results showed a significant main effect for production of reference of time: F (2, 12) = 65.730, p = .000. Reference
to the past was significantly impaired compared with reference to the present
(t (12) = 8.23, p = 0.0001), and to the future (t (12) = 8.09, p = .0001). There
was no difference between regular and irregular past tense forms (t (12) = 0.71,
p = .49) (see Appendix 3.1). There was also no significant difference between
reference to the present and to the future (t (12) = 0.00, p = 1.000). The
results on the Swahili version of the test showed a similar pattern: there was
again a significant effect for reference of time: F (2, 12) = 13.551, p = .002.
The agrammatic speakers performed poorly on reference to the past compared
with reference to the present (t (12) = 3.39, p = .0054) and to the future (t
(12) = 4.28, p = .0011). However, no significant difference between reference
to the present and the future was found (t (12) = 0.62, p = .5486). Overall,
the production of English past (mean = 9.69) was significantly worse than the
production of Swahili past (mean = 16.46) (t (12) = 6.60, p = .0001).
3.3.3
Comprehension in English and Swahili
The comprehension results are presented in Table 3.3.
The pattern of performance on comprehension of reference of time was quite
similar to that on production. For English comprehension, a significant main
effect was found: F (2, 12) = 16.434, p = .001. Comprehension of English
reference to the past was significantly more challenging than reference to both
the present (t (12) = 4.10, p = .0015) and the future (t (12) = 4.04, p = .0016).
There was no effect of regularity of English past tense (t (12) = 0.55, p = .59)
(see Appendix 3.1), meaning that the poor performance on English past tense
was not due to the irregularity of some of the verbs. Again, no significant
difference between reference to the present and to the future was found (t (12)
= 1.00, p = .3370). The performance on Swahili showed a relatively similar
pattern, there was a significant main effect for comprehension of reference of
time: F (2, 12) = 19.648, p = .000). Comprehension of Swahili reference to
the past was more challenging than Swahili reference to the present (t (12) =
4.57, p = .0006) and to the future (t (12) = 4.63, p = 0.0006). The difference
in performance between Swahili reference to the present and to the future was
not significant (t (12) = 1.48, p = .1654). The performance on comprehension
of English reference to the past (mean = 14.92) was significantly worse than
comprehension of the Swahili reference to the past (mean = 17.46) (t (12) =
3.3. RESULTS
79
2.75, p = .0177).
Table 3.3: The comparison of agrammatic speakers’ scores on comprehension of reference of
time in Swahili and English.
SW
HJ
LA
MM
JK
EA
PN
JA
MW
VK
HS
JN
SS
mean
3.3.4
Swahili Comprehension
Past Present Future
English Comprehension
Past Present Future
19
17
17
20
20
19
15
17
15
18
19
15
16
17.46
20
7
17
20
20
18
9
16
15
11
15
12
14
14.92
20
20
20
20
20
19
20
20
20
20
20
20
20
19.92
20
18
19
20
20
20
19
20
20
20
20
19
20
19.61
20
19
20
20
19
19
20
20
20
20
20
20
20
19.77
20
19
19
20
20
19
20
20
19
20
20
20
19
19.62
Individual results on production and
comprehension of English and Swahili past
On further analysis of individual results of each agrammatic speaker, a discrepancy on individual performance is observed on production as well comprehension of time reference on both languages. The English production data
show that all the agrammatic speakers had problems with reference to past.
However, on the Swahili production data, three agrammatic speakers (LA, MM
and JK) did not make any errors with past. This shows that with respect to
production, reference to the past was more vulnerable in English than Swahili
(See Table 2 above).
For comprehension, the English comprehension data show that three agrammatic speakers (SW, MM, and JK) performed quite well on reference to the
past, whereas, on Swahili comprehension, two of them (MM and JK) performed
similarly quite well on reference to the Swahili past. It is clear that the two
patients (MM and JK) had no difficulty comprehending past in both Swahili
80
CHAPTER 3. TIME REFERENCE PRODUCTION AND COMPREHENSION
and English (See Table 3).
In conclusion, all agrammatic speakers had difficulty with production of the
English past, implying that reference to the past is a problem to all the agrammatic speakers, but not all agrammatic speakers are equally affected on both
languages. However, further analyses all the data show a significant correlation
in agrammatic performance between English and Swahili in production (R (37)
= 0.68, p < .001 and in comprehension (R (37) = 0.80, p < .001; implying that
agrammatic speakers who are poor in English are also poor in Swahili and the
other way around. Again, at the subtest level, there was a significant correlation
between production and comprehension10 in English (R (37) = .81, p < .001,
and in Swahili (R (37) = .35, p < .029), indicating that agrammatic speakers
who performed poorly in production also performed poorly in comprehension
(and vice versa).
3.3.5
Error types
The distribution of error types of the agrammatic speakers is presented in Table
3.4.
Incorrect responses of the agrammatic speakers on the production task were
distinguished into three error types: substitutions by other forms of the same
verb, omissions of verb inflections and others. Substitution errors were equally
prevalent in both Swahili and English tasks (t (12) = 0.73, p = .48). On
the Swahili task, the past tense marker ‘li’ was frequently substituted with
the present tense marker ‘na’. On the English task, the past time frame was
substituted most frequently with the present time frame (either simple present
or the present progressive). However, errors of omission were more prevalent
on the English test than on the Swahili test (t (12) = 4.9, p = .0004). The
agrammatic speakers quite often omitted the tense inflection in English (eg.
‘-ed’ for past). In a few instances in Swahili, they omitted both the subjectagreement prefix and the tense prefix. Other type of errors noted were a few
regularization errors in English: some of the agrammatic speakers regularized
the English past in irregular verbs (e.g. ‘sweeped’).
10 The
comprehension task is a binary choice test, which makes a comparison between
comprehension and production based on raw scores less valid. Therefore, the scores on
the comprehension task were corrected for guessing, using the formula: Corrected score
= #correct [# incorrect: (#alternatives-1)].
3.4. DISCUSSION
81
Table 3.4: Distribution of error types on production of individual agrammatic speakers
Swahili production errors
Substitutions Omissions Others
SW
HJ
LA
MM
JK
EA
PN
JA
MW
VK
HS
JN
SS
mean
3.4
9
1
0
0
0
15
3
1
6
6
3
5
5
4.15
0
2
1
0
1
5
0
0
0
1
0
0
0
0.78
0
0
0
0
0
0
0
0
0
0
0
0
0
0
English production errors
Substitutions Omissions Others
6
10
3
0
2
0
9
5
11
3
6
11
4
5.38
5
5
0
5
0
16
6
4
2
8
5
5
5
5.08
0
1
0
0
0
1
0
0
0
0
0
0
0
0.15
Discussion
The present study examined the production and comprehension abilities of
bilingual agrammatic speakers in regard to time reference. The results revealed that the agrammatic speakers were impaired in their production and
comprehension of time reference to the past. However, their production and
comprehension of time reference to both the present and the future are relatively spared. A similar pattern of impairment is reflected in both languages,
Swahili and English, irrespective of their morphological differences. These findings are discussed in relation to the theories of agrammatism mentioned in the
introduction.
3.4.1
Why time reference to the past is difficult for
agrammatic speakers
Friedmann and Grodzinsky’s (1997) TPH, argues that the agrammatic representation of the syntactic tree is pruned at the position of the Tense node. As
82
CHAPTER 3. TIME REFERENCE PRODUCTION AND COMPREHENSION
a result, the tense node is inaccessible to agrammatic speakers. The authors,
therefore, predict that Tense should be impaired for both languages irrespective
of time-frame. We do not find this account compatible with the present data
because it cannot explain the selective impairment we found for reference to
the past in both languages. An inaccessible Tense node should lead to random
distribution of errors over the tested categories (past, present and the future
in English and Swahili); however, this was not the case in the present study.
The TUH (Wenzlaff and Clahsen, 2004) and TAUH (Burchert et al., 2005)
concur that it is not the position of tense in the syntactic tree that is causing
problems, but the characteristics of Tense. The authors argue that the interpretable features of Tense that are used for time reference are underspecified in
agrammatic speakers. Tense inflection must be checked against the time-frame
the proposition is referring to. This requires an extra-sentential computation
which is usually difficult for agrammatic speakers. However, this explanation
cannot adequately account the specific problem with reference to the past evidenced in this study and in several other studies (Bastiaanse, 2008; Bastiaanse
et al., 2011; Jonkers & De Bruin, 2009; Nanousi et al., 2006; Stavrakaki &
Kouvava, 2004; Yarbay Duman & Bastiaanse, 2009). Generally speaking, all
these theories (TPH, TUH and TAUH) restrict themselves to Tense; they do
not explain the problems agrammatic speakers have with verb forms expressing
time reference through Aspect inflection, nor through periphrastic forms.
Reference to the future is relatively spared, both in production and in comprehension. For English, that may be explained by its simple form: an invariant
auxiliary that is not inflected for person and number and an infinitive. However,
this does not hold for Swahili, where reference to the past, present and future
are marked by inflections within the verb. In other languages, performance
on present and future are also relatively spared compared to reference to the
past, for example, for Turkish, which is an agglutinative language, like Swahili.
According to Zagona (in press), future is a variant of present. Together, they
are ‘non-past’, and therefore, reference to the future is not discourse linked.
The PADILIH of Bastiaanse et al. (2011) apparently accounts best for the
current data. The PADILIH is based on the idea that reference to the past
through grammatical morphology (Tense and Aspect) is discourse linked, reference to the past, therefore, requires extra processing load (Avrutin, 2000;
2006), These extra processing resources are not sufficiently available in the
affected brain areas of the agrammatic speakers. Notice that ‘discourse link-
3.4. DISCUSSION
83
ing’ or ‘processing by discourse syntax’ does not mean that there should be
a linguistic context. It means that a linguistic element (in this case the verb
inflection for time reference) should be linked to an extra-sentential context,
which may or may not be text. Thus, it is processing at the syntax-semantic
interface. In the sentence completion test, there was linguistic discourse: there
was an introductory sentence and a lexical adverb referring to past, present
or future. In the comprehension test, the processing at the level of discourse
context had to be done solely on the basis of the past tense inflectional marker.
When hearing a past tense inflection, the hearer must process at the level of
discourse syntax, since the time of speaking and the time of the event do not
coincide.
3.4.2
Why reference to the past is worse in English than
in Swahili
One may propose the influence of the native language of the agrammatic speakers as an alternative explanation for the slightly better performance in Swahili
past. However, we do not think this is the case. As mentioned, Swahili is a
Bantu language, whereas English is not. Apart from the acquisition of both
Swahili and English at an early age, the agrammatic speakers acquired another language from birth, which is classified either as Bantu, Nilotic or IndoAryan. Bantu languages, like Swahili, express time reference through a very
rich and distinct Tense morphology. Similarly, Indo-Aryan expresses time reference through Tense. Nilotic languages, on the contrary, express time reference through Aspect. Furthermore, in Nilotic languages, both perfective and
imperfective Aspect are distinguished based on tone rather than on grammatical morphemes (Dimmendaal, 2001). Of the thirteen agrammatic participants,
eight acquired Bantu, while the rest acquired Nilotic and Indo-Aryan languages,
respectively, as first languages. Although these first languages have different
ways of expressing time reference, we still find a similar pattern of impaired
reference to the past in Swahili in all the agrammatic speakers. Furthermore,
we did not find any differences on performance on reference to the past between native speakers of Bantu and native speakers of other languages (Nilotic
and Indo-Aryan). Therefore, we do not think that the structure of the earliest
learned language explains the better performance in Swahili. The better performance on Swahili (compared to English) is shown consistently in our studies
(Abuom et al, 2011; Abuom & Bastiaanse (2012).
84
CHAPTER 3. TIME REFERENCE PRODUCTION AND COMPREHENSION
According to Bates et al. (1987)’ cue cost theory, morphologically complex paradigms are likely to yield more errors than morphologically simple
paradigms. Since the Swahili verb morphology paradigm is large compared
to the English paradigm, Bates et al. (1987) predict worse performance in
Swahili than English. What we found is the opposite: Swahili is better preserved than English. The cue validity theory (Bates et al., 1991) predicted
equal performance in both languages and no difference between past, present
and future. This is also the wrong prediction. There is a selective deficit for
Time Reference to the past, but past reference in Swahili is better preserved
than in English. The reason may be that Swahili’s large and complex verb
paradigm consists of several morphologically important affixes attached to the
verb root. An omission of any single morpheme including tense prefix from
the Swahili verb paradigm would render it a non-word, whereas an omission
of past Tense suffix (-ed) does not render the English verb a non-word. Given
their morphological importance, the affixes on the Swahili verb paradigm are
generally more firmly anchored in the language system, than the affixes on the
English verb. We, therefore, think Bates and colleagues’ (1987; 1991) assumption cannot explain the quantitative difference between the languages, nor can
it explain the selective deficit for verb forms referring to the past. Interestingly,
for this single category (past tense), English is more complex with its multiple
regular allophones and irregular past tense forms.
A better explanation is based on the morphological differences regarding
the past Tense marker on both languages. While Swahili past Tense has only
a single invariant, regular form marked as a prefix on the verb paradigm, the
English past Tense has both regular (with different phonetic realizations: /d/,
/t/, and /Id/) and irregular forms. It may thus be the case that English past
Tense requires more processing resources compared to Swahili past Tense: the
agrammatic speaker has to consistently monitor whether the English past Tense
takes regular or irregular form; and appropriately select the correct phonetic
realization for the regular past Tense. This assumption is in fact in line with
the findings of Tsapkini, Jarema & Kehayia (2001): their Greek agrammatic
speaker had particular difficulty with reference to the past. They attributed
this difficulty to Greek verb morphology which is characterized by several allomorphs specifying Tense and Aspect.
In Abuom & Bastiaanse (2012), we argued that apart from the differences
in morphological complexity of the two languages, Swahili and English, the
3.4. DISCUSSION
85
regularity of the Tense affixes may also play a role. It has been suggested that
bilingual agrammatic speakers are likely to perform better in a language with
complex but regular morphology than in a language with simple but not regular
morphology (Goral, 2011). In usage-based frameworks such as Bybee (2007)
and Dressler (1985), regular morphological process is associated with affixation
and considered to be more ‘natural’, highly frequent in most languages and
generally easier to process. In contrast, irregular morphological processes are
associated with stem change and considered to be less ‘natural’, infrequent in
most languages and generally difficult to master. Although we did not find
any dissociation between regular and irregular past Tense verbs in English, the
fact that irregular forms exist may make the whole category more difficult to
process than members of the very regular Swahili paradigm. Some studies have
shown that individuals with impaired linguistic abilities, such as agrammatic
speakers, prefer to produce highly frequent linguistic morphemes over less frequent linguistic items in their speech (see Centeno & Anderson 2011; Abuom
& Bastiaanse, 2012). This suggests that affixation is preferable to stem change
in linguistically impaired populations since affixes are more common within a
single language and easier to process in general than stem changes. Swahili
verb morphology for past Tense is regular (involves affixation) hence highly
predictable and of high frequency compared to English past Tense which can
be both regular and irregular, consisting of instances of infrequent affixations
and internal stem changes. We, therefore, think Goral’s (2011) idea is a likely
explanation for the different performance levels in Swahili and in English in
the current study.
In sum, reference to the past through verb morphology was impaired in these
bilingual agrammatic individuals, both in production and in comprehension
in both languages, as predicted by the PADILIH. The strong correlations in
agrammatic speakers’ performance between the two languages show that there
is one central deficit underlying the general performance patterns. However,
the impairment was less severe in the language with the most complex, but also
most regular paradigm, as suggested by Goral (2011), implying a compounding
effect of the morphological system and reference to the past.
86
CHAPTER
4
Sentence Comprehension in Swahili-English bilingual
agrammatic speakers
Abstract
For this study, sentence comprehension was tested in Swahili-English bilingual
agrammatic speakers. The sentences were controlled for four factors: (1) order
of the arguments (base vs derived); (2) embedding (declarative vs. relative
sentences); (3) overt use of the relative pronoun ‘who’; (4) language (English
and Swahili). Two theories were tested: the Trace Deletion Hypothesis (TDH;
Grodzinsky, 1995), that assumes a representational deficit in agrammatic aphasia and the Derived Order Problem Hypothesis (DOP-H; Bastiaanse & Van
Zonneveld, 2005), which is a processing account. Both theories have the same
predictions for sentences in derived order. The difference is that the TDH predicts chance level performance for sentences in which the arguments are not in
base order, whereas the DOP-H predicts poorer performance when processing
This study has been published as:
Abuom, T., Shah, E., & Bastiaanse, R. (2013). Sentence Comprehension in SwahiliEnglish bilingual agrammatic speakers.Journal of Clinical Linguistics & Phonetics, 27,
355-370.
87
88
CHAPTER 4. SENTENCE COMPREHENSION
demands increase.
The results show that word order influences performance, in that sentences
in which the arguments are in derived order are harder to comprehend than
sentences in which the arguments are in base order. However, there is a significant interaction with the factor ‘embedding’: sentences with an embedding
are harder to comprehend than simple declaratives and this influence is larger
in derived order sentences. There is no effect of language, nor of the use of a
relative pronoun. These results are correctly accounted for by the DOP-H.
4.1
Introduction
Individuals with agrammatic Broca’s aphasia are generally assumed not only to
produce slow and effortful speech, with short phrases consisting of mainly content words, but also to have a relatively intact language comprehension ability.
However, there is substantial empirical evidence to suggest that certain linguistically complex sentence types are difficult to comprehend for monolingual
agrammatic speakers (cf. Caramazza & Zurif 1976; Grodzinsky 2000; Bastiaanse & Edwards, 2004). Particularly vulnerable are the semantically reversible
sentences whose arguments are not in their base position, such as object clefts,
passives, and object relative sentences. Several theories have been formulated to
account for this phenomenon, some of which have contributed substantially to
our understanding of language comprehension in individuals with agrammatic
Broca’s aphasia. However, the focus has been almost exclusively on monolingual speakers, with hardly any attention given to comprehension patterns in
bilinguals, especially to speakers of two morphologically different languages.
The current study examines comprehension patterns in pre-morbidly highly
proficient bilingual speakers of Swahili and English, two languages that possess
contrasting morphological and syntactic properties. We start by giving some
background on relevant Swahili syntax and verb morphology. Next, we provide an overview of comprehension theories in agrammatic aphasia. This will
be followed by a review of some previous studies on Swahili-English bilingual
agrammatic aphasia. We conclude the introduction by providing the aims and
predictions for the current study.
4.1. INTRODUCTION
4.1.1
89
Swahili syntax and verb morphology
Syntax (word order)
According to Ashton (1982), Swahili, like many other Bantu languages, is a
highly agglutinating and mostly prefixing language with a fairly fixed base
word order (subject / agent - verb - object / theme: SVO), where the agent
precedes the verb and the theme (see 1a-b). Although the second illustration
(1b) is a subject relative clause, the agent and theme maintain the base order. We call these ‘base order sentences’. Sentences with derived order of the
arguments, such as passives (subject / theme - verb - Prepositional Phrase /
agent), object relatives (object / theme - subject / agent - verb) with and without complimentizer are also possible. These we call ‘derived order sentences’.
In derived order sentences, the arguments are no longer in their base positions
as exemplified in (2a-b).
(1)
(a)
Base order, simple active (agent - theme)
Kijana a-na-m-gonga
msichana
Boy
s/he-PRESENT-him/her-hit girl
‘The boy is hitting the girl’
(b)
Base order, subject relative (agent - theme)
Kijana ambaye a-na-m-gonga
msichana
Boy
who
s/he-PRESENT-him/her-hit girl
‘The boy who is hitting the girl’...
(2)
(a)
Derived order, passive (theme - agent)
na kijana
Msichana a-na-gong-wa
s/he-PRESENT-hit-PASSIVE by boy
Girl
‘The girl is hit by the boy’...
90
(b)
CHAPTER 4. SENTENCE COMPREHENSION
Derived order, object relative + relative pronoun (theme - agent)
Msichana ambaye kijana a-na-m-gonga
Girl
who
boy
s/he-PRESENT-him/her-hit
‘The girl who the boy is hitting’ ...
(c)
Derived order, object relative - relative pronoun (theme - agent)
Msichana kijana a-na-m-gonga
Girl
boy
s/he-PRESENT-him/her-hit
‘The girl the boy is hitting’...
In a passive sentence (2a), the theme is in clause-initial position, and the
agent is in postverbal position in the prepositional phrase. The final suffix
of the verb complex also changes from ‘-a’ to passive marker ‘-wa’. As in
English, the phrase ‘na’ (by) is included only if the information that follows
is important for clarity purposes to the reader or the listener. In an object
relative sentence (2b), the theme is in initial position, the relative pronoun
‘ambaye’ (who) preludes the embedded sentence. However, just like in English,
the relative pronoun may be left out, as shown in (2c).
Verb Morphology
The Swahili verb morphology is distinctly more complex than that of English,
consisting of numerous affixes, both inflectional and derivational morphemes,
attached to the verb root. These affixes (prefixes and suffixes) must occupy
specific positions and they perform specific functions. The general position
scheme of the affixes in relation to the verb root is shown in (3a). Some
illustrations from Abuom et al. (2011) are given in (3b-d).
(3)
(a)
Pre-prefix (Pp) + Subject prefix (Sp) + Tense marker (T) + Object
prefix (Op) + ROOT + derivation (d) + Suffix (s) + Post-suffix (Ps).
(b)
A + li + m + gong
+ a
Sp + T + Op + ROOT + d
“S/he hit him/her”
4.1. INTRODUCTION
(c)
91
Ha + tu + ta + m + gong
+ a
Pp + Sp + T + Op + ROOT + d
“We will not hit him/her”
(d)
Tu + na + gong
+ a + n + a
Sp + T + ROOT + d + S + Ps
“We are hitting each other”
As illustrated in (3b-d), the Swahili verb complex, unlike that of English,
can function as a complete sentence. The verbal complex consists of: the
subject prefix (subject-verb agreement), the tense marker (includes tense and
aspect) and the verb root, which are generally obligatory in every grammatical
Swahili sentences. However, the object prefix is generally not obligatory when
the object of the sentence is overtly present. The subject and object prefixes
must always agree in number with the subject and the object of the sentence
respectively.
4.1.2
Two theories on sentence comprehension in
agrammatic Brocas’s aphasia
Several linguistic theories have been proposed to account for the sentence comprehension deficit in monolingual agrammatic individuals11 . We discuss two
theories here that formed the basis of this study. The Trace Deletion Hypothesis (TDH) proposed by Grodzinsky (1984) which has undergone a series of
revisions (Grodzinsky, 1986; 1995; Drai & Grodzinsky, 2006) finds its origin
in Chomsky’s Universal Grammar (see, e.g. Chomsky, 1995). According to
this theory, constituents can ‘move out’ their original position, leaving behind
a ‘trace’. The trace and the antecedent are, thus, linked as shown by coindexation in (4a-c). The thematic roles are assigned to the original positions
in the sentences by the verb and they are transferred to the ‘moved’ constituent
via the trace.
11 For
comprehension studies, the term Brocas aphasia is often used. We prefer the term
agrammatic aphasia here, to show that our participants were not only suffering from
Brocas aphasia, but also spoke in telegraphic speech.
92
CHAPTER 4. SENTENCE COMPREHENSION
(4)
(a)
The boyi is hit i by the girl.
(b)
The boyi whoi the girl is hitting i ...
(c)
The boyi the girl is hitting i ...
According to Grodzinsky’s TDH, in individuals with agrammatic aphasia, the traces are deleted from the sentence representation due to damage
to Broca’s area. As a result, the verb cannot assign a thematic role to the
moved constituent. In order to interpret such sentences, the agrammatic individuals apply a non-syntactic ‘default strategy’ and assign an agent role to the
first NP (‘the boy’) because usually the first NP is the agent. The second NP
also gets an agent role, directly assigned by the verb. As a result, the aphasic
individuals are faced with a representation consisting of two agents (the boy
and the girl) and they have to guess, leading to chance level performance. In
subject relatives (‘the boy who is hitting the girl...’), ‘the boy’ is not assigned a
thematic role either, because the NP has been moved from its original position
and the trace is deleted. However, the default strategy assigns the agent role
to this first NP and the verb assigns the theme role to the second NP, resulting
in a correct interpretation of the sentence.
It is important to note that the TDH assumes that individuals with agrammatic aphasia suffer from a representational deficit. The sentence representations are damaged because the traces are lost. This means that they always
apply the default strategy: they can never assign a thematic role to a moved
argument. Therefore, their performance will be at chance for all sentences in
which the order of the thematic roles is non-canonical (between 33-67% correct
on a binary choice test) and above chance on sentences where the agent is in
first position.
The Derived Order Problem Hypothesis (DOP-H) has a larger scope than
the TDH and it is meant to describe the production and comprehension deficits
in agrammatic aphasia. It is based on data from many languages (Dutch, English, Turkish, Italian; see, for example, Bastiaanse et al., 2003; Bastiaanse
& Thompson, 2003; Bastiaanse & Van Zonneveld, 2005; 2006; Yarbay Duman et al., 2007; 2008; 2011). Contrary to the TDH, it does not assume a
representational deficit, but a processing disorder, meaning that the sentence
4.1. INTRODUCTION
93
representations are intact, but linguistic operations cannot always be performed
correctly. The more complex the operations are, the more difficult processing
will be. The underlying idea is that each language has a base order in which
constituents that naturally belong together are adjacent. In English, for example, the base word order is Subject-Verb-Object (SVO), whereas, in Dutch
and German it is Subject-Object-Verb (SOV). All other word orders are derived. Notice that the DOP-H is relatively theory-free: although embedded in
the Chomskyan tradition, there is no strong idea about movement, merging, or
traces. The DOP-H assumes that in order to produce or comprehend a derived
word order sentence, extra grammatical operations have to be performed and
this is exactly what is difficult for agrammatic speakers. For production this
means that predominantly simple, base order sentences will be produced and
for comprehension that semantically-reversible sentences with derived order of
the arguments will be poorly understood. The DOP-H assumes, just like the
TDH, that agrammatic individuals, when faced with a sentence with derived
word order, may resort to a default strategy that the first NP is the agent. The
main difference between the TDH and the DOP-H is that the DOP-H does
not assume that the agrammatic individuals can never parse (or produce) a
sentence with derived order of the arguments correctly; they cannot do this
correctly all the time and the more processing is required, the more errors they
will make. With regard to performance level this implies that the TDH predicts chance level performance for all sentence types with derived order of the
arguments. The DOP-H predicts poorer performance on sentences in which the
order of the arguments is derived and that when further complexity is added,
performance will further decrease.
In a study similar to the current one, Yarbay Duman et al. (2011) studied
agrammatic sentence comprehension in Turkish. Turkish has a relatively free
word order and a complex case system. Interestingly, some derived word order
sentence types require a special case assignment system. For example, in object
relatives, the subject has genitive case and the object has nominative case.
Yarbay et al. (2011) found an interaction effect of word order and case: when
case was not according to its default distribution (subject = nominative, object
= accusative), performance diminished. This is compatible with a processing
account like the DOP-H: comprehension of sentences with derived order of the
arguments is impaired due to a processing disorder; adding complexity to these
derived order sentences further diminishes performance.
94
CHAPTER 4. SENTENCE COMPREHENSION
In sum, both the TDH and DOP-H predict that agrammatic speakers have
difficulty understanding sentences in derived word order. While TDH predicts
above chance level performance for base order sentences and chance level performance for derived order sentences, the DOP-H predicts better performance
for base order sentences than for derived order sentences and further decline of
performance when linguistic complexity is added to the sentence.
There are two other accounts that could be relevant to our study. The first
has to do with Working Memory (WM). It has been argued that comprehension of derived order sentences can be impaired because of an overload on the
aphasic individuals’ working memory capacity which is generally assumed to
be impaired (Burgio & Basso, 1997; Ivanova & Hallowell, 2012; King & Just,
1991; Miyake, Carpenter & Just, 1994). The question is, of course, how WM
impairments may affect comprehension of some sentence types but not of others, that is, what units and / or processes influence the WM operations? It has
been argued that the number of words may play a role, or rather the number of
lexical items. The number of lexical items is the same in our sentences, but the
number of words varies. Interestingly, the sentences are consistently shorter in
Swahili than in English. Thus, if one accepts that more words in a sentence
negatively affect agrammatic performance, then the Swahili-English bilingual
agrammatic individuals should perform worse in English than in Swahili. An
alternative WM account argues that it is the distance between the filler and the
gap which is critical, that is, the more words between the filler (the argument
that has been extracted from its base position) and the gap, (the resulting
‘empty’ base position), the harder it is to process the sentences, because the
time that the filler should be kept in (the impaired) WM is longer (e.g. Frazier
& Friederici, 1991; but see Friedmann & Gvion, 2003 and Gvion & Friedmann,
2012 for counter evidence). For checking this, a study on bilingual aphasia
is particularly interesting, because, again, this distance is consistently shorter
in all Swahili derived word order sentences than in the English counterparts.
However, this account makes predictions for within language comparison as
well. For example, for English, performance should be better on the object
relatives without complementizer, since the distance is one word shorter. Another suggestion with respect to WM is that in long sentences the middle part
is lost due to the WM deficit. In (5a-c) the resulting structures are given.
4.1. INTRODUCTION
95
(5)
(a)
passive
the man is rescued by the woman → the man ... the woman
(b)
subject relative
(...) the woman who rescues the man → the woman ... the man
(c)
object relative
(...) the man (who) the woman rescues → the man ... rescues
If one assumes something like a default strategy that makes the agrammatic
individual assign the agent role to the first NP, then comprehension of passives
and object relatives will be impaired on a binary choice test if the distractor
depicts the same action as the target picture, but with the thematic roles
reversed. They will perform relatively well on the subject relatives. However,
when a test with four pictures is used, in which the two extra alternatives
depict a different action with the same participants (one with the same agent theme relation as in the target sentence and one with the roles reversed), then
the agrammatic individuals will point to one of the lexical distractors when
hearing a subject relative or a passive, because the verb is wiped from WM.
Although not the major focus of the current paper, we will address this WM
account in the Discussion section.
The data from Swahili-English bilingual agrammatic speakers provide a
valuable site for testing the prediction of these theories, as these languages
differ in their morpho-syntax: while English has relatively simple morphology,
Swahili has a markedly agglutinative morphology with an extra passive marker
on the verb. The question for the present study is whether the passive marker
on the verb influences performance in Swahili.
4.1.3
Previous studies on Swahili-English bilingual
agrammatic aphasia
For the present study, the term ‘bilingual’ has been used to include multilingual
persons who speak two or more languages or dialects in their everyday lives
(Grosjean, 1994). It has been reported in several studies on bilingual aphasia
that most individuals suffer from the same type of aphasia in all their languages
acquired before an aphasia-producing incident; and the recovery pattern is often parallel (Fabbro, 1999, 2001; Paradis, 2001; Miozzo, Costa, Hernandez &
96
CHAPTER 4. SENTENCE COMPREHENSION
Rapp, 2010; Abutalebi, Cappa, & Perani, 2005), however, non-parallel recovery
patterns have also been reported (Albert & Obler, 1978; Fabbro, 1999). The
differential recovery patterns are argued to stem from differences in the age of
acquisition, frequency of use or proficiency level between the languages acquired
before an aphasia producing incident. The aphasic participants in the present
study are all balanced and proficient bilinguals, who acquired all their three
languages (native language, Swahili and English) early in life. It is generally
assumed that such bilinguals have shared language processing brain regions
(e.g., Abutalebi et al., 2005; Miozzo et al., 2010). One of the consequences of
shared language processing regions has been reflected in the limited number
of studies that we have conducted on Swahili-English agrammatic speakers.
In our first study, Abuom and Bastiaanse (2012), we analysed the production
of verb forms for reference to the past and to the present in the spontaneous
speech of early balanced agrammatic individuals. The proportion of verb forms
referring to the present was normal in their spontaneous speech, but the proportion of verb forms referring to the past was significantly lower than normal.
The pattern of performance in both languages was parallel. In our second
study (Abuom & Bastiaanse, 2013), agrammatic speakers were tested on production and comprehension of verb forms referring to the past, present and
future, using both sentence completion and sentence-picture matching tasks.
Their performance showed a selective deficit of reference to the past on both
comprehension and production tasks. Again, the pattern of performance was
similar in both languages in spite of the morphological differences.
What these studies show is that Swahili-English agrammatic speakers have
a selective difficulty producing and comprehending sentences in base word order referring to a past time frame, but not to a present time frame. How they
produce or comprehend sentences in derived word order is not known yet. The
difficulty with base order sentences in the past time frame, which has been
found in several other languages in monolingual agrammatic individuals (Bastiaanse et al., 2011; Bastiaanse, 2013), is reflected similarly in both languages of
Swahili-English bilingual speakers. It is, however, unclear whether the difficulty
with comprehension of sentences in derived word order, found in monolingual
studies of other several languages (Dutch, English, Turkish, and German), is
reflected in a similar way in Swahili-English bilingual agrammatic individuals.
Furthermore, it is interesting to find out if the difficulty with derived order
sentences affects both languages of bilinguals in a similar way, quantitatively
4.1. INTRODUCTION
97
and qualitatively.
4.1.4
The predictions for the current study
Based on the studies of spontaneous speech and time reference in bilingual
Swahili-English agrammatic speakers, we expect similar performance across the
two languages regardless of the morphological differences in their verb inflection
systems.
With respect to the empirical validity of the two theories (TDH and DOPH) in Swahili-English bilingual agrammatic individuals the following is predicted. The TDH (Grodzinsky, 1986; 1995; Drai & Grodzinsky, 2006) predicts
(a) above chance level performance for sentences in which the order of the arguments is canonical: active and subject relative sentences in both languages;
(b) chance level performance for sentences in which the theme precedes the
agent: passive, object relative sentences with and without relative pronoun.
The DOP-H (Bastiaanse & Van Zonneveld, 2005) predicts (a) good performance for sentences with the arguments in base order: active and subject
relative sentences; (b) poor performance on sentences with derived order of
the arguments: passive, object relatives with and without relative pronoun.
Furthermore, the DOP-H assumes that added linguistic complexity will lead to
additional problems understanding sentences with derived order of the arguments. It is, thus, expected that the extra operation needed for the embedding
will influence parsing. In other words, the DOP-H predicts an interaction effect
of derived order and embedding, so that it predicts: simple active < subject
relative < passive < object relative relative pronoun.
In Swahili, the finite verb is morphologically more complex than in English
and the study of Yarbay Duman et al. (2011) showed that case morphology
interacts with derived order. However, case is a crucial factor for sentence
comprehension in Turkish and depends on the sentence type. This is not so for
Swahili verb morphology for most sentence types. However, it may be that the
passive marker on the verb in Swahili facilitates or complicates performance.
This can be accounted for by the DOP-H, but not by the TDH.
A WM account predicts poorer performance on longer sentences or longer
filler - gap distances. It predicts typical performance: role reversals in passives
and lexical (+ role reversals) in object clefts.
A final point that should be mentioned is that it is not a priori clear whether
we should expect similar impairments in the two languages of the bilingual
98
CHAPTER 4. SENTENCE COMPREHENSION
agrammatic individuals. According to Paradis (1988) and Fabbro (2001) a central underlying deficit in bilingual individuals with agrammatic aphasia may
cause different surface manifestations in the languages that differ in their grammatical morphology. Taking into account the results of our previous studies in
a Swahili-English bilingual agrammatic population, we expect to find similar
patterns in both languages, although the extra verb morpheme in Swahili passives may lead to poorer performance in Swahili than English on this sentence
type.
4.2
4.2.1
Methods
Participants
There were 11 non-fluent aphasic/agrammatic and 11 non-brain-damaged
(NBD) participants in the study12 . Each participant spoke a Bantu or Nilotic
or Indo-Aryan language natively, but all spoke English and Swahili as second
languages, learned from 4 years old at school. The NBDs were, as a group,
matched on age, native language, and education (a minimum of high school
diploma: over 12 years of uninterrupted exposure to English and Swahili) with
the agrammatic individuals. The agrammatic individuals were pre-morbidly
highly proficient in the two second languages. All participants were righthanded and without a history of psychiatric or developmental speech or language disorders or any other neurological conditions. The aphasic individuals
were assessed and diagnosed as suffering from aphasia by both the neurologist and speech therapist at the speech therapy department of the Aga Khan
University hospital. The speech therapist confirmed that all the aphasic participants produced speech that was clinically judged as non-fluent and ‘telegraphic’ (slow, effortful with short and simple utterances consisting of mainly
content words)13 . Their comprehension of single words in both languages was
relatively good, based on their performance on an adapted version of the sub12 With
the exception of 1 agrammatic individual (BM), the agrammatic participants participated in a previous study on time reference (see Abuom & Bastiaanse, 2013). Three
of the agrammatic individuals (EA, MM & HJ) had also participated in an earlier study
on bilingual agrammatic spontaneous speech (see Abuom & Bastiaanse, 2012).
13 Unfortunately, in Kenya there are no tests available to establish the aphasia syndrome.
The BDAE cannot be used to classify the aphasia type in Kenya because of cultural
bias.
4.2. METHODS
99
task for auditory comprehension of single words (nouns, verbs, colors, shapes,
letters, numbers) from the Boston Diagnostic Aphasia Examination (BDAE:
Goodglass & Kaplan, 1972). A few pictures of this task were substituted,
because some items are unknown in Kenya and, hence, no Swahili word was
available (for example, the hammock was changed to a swing). The level of
comprehension of sentences in both languages was also found to be comparable
based on their performance on a syntactic comprehension test (t (10) = 0.48,
p = 0.64), a sub-test of Bilingual Aphasia Test (BAT: Paradis & Mwansau,
1990). The demographic details of the participants and their scores on the
BDAE subtest for auditory word comprehension and on the BAT subtest for
syntactic comprehension are shown in the Table 4.1. Considering their agrammatic output in both languages and their relatively good comprehension, it is
assumed that they suffer from classical Broca’s aphasia.
Table 4.1: Demographic details of the agrammatic individuals and their scores (% correct)
on the test for auditory comprehension of words (on an adapted version of the
BDAE-test) and on the subtest of Bilingual aphasia Test (BAT) in Swahili and
English.
EA
JN
SS
PN
MM
JA
MW
HJ
VK
HS
BM
Mean
4.2.2
Age
(years)
Gender
Handedness
Education
(years)
Years
post
stroke/
head
trauma
Native
language
Swahili
BDAEsubtest
scores
English
BDAEsubtest
scores
Swahili
BATsubtest
scores
English
BATsubtest
scores
42
50
30
36
47
46
50
45
25
64
53
44.36
M
F
F
F
F
M
F
F
F
M
F
R
R
R
R
R
R
R
R
R
R
R
16
13
12
14
16
16
16
14
16
16
12
14.64
17
10
17
1
10
1
1.5
10
2
1
0.5
6.45
Nilotic
Bantu
Indo-Aryan
Bantu
Nilotic
Bantu
Bantu
Nilotic
Bantu
Indo-Aryan
Bantu
100
100
100
100
100
100
98.6
100
100
99
100
99.8
99
100
99
100
100
100
100
100
98.6
98.6
100
99.6
59
74
64
60
83
67
66
64
86
64
66
68.5
60
57
71
70
83
63
67
64
84
60
63
67.5
Materials and procedure
An adaptation of the sub-test of the Verb and Sentence Test (Bastiaanse et
al., 2002; 2003) for sentence comprehension to Swahili and English was used
to test whether word order, embedding and verb complexity influence comprehension differently in the two languages of bilingual agrammatic individuals.
The task in each language included 200 semantically reversible sentences (all in
the present time frame) distributed equally into five sentence types: 40 active
100
CHAPTER 4. SENTENCE COMPREHENSION
sentences; 40 passive sentences; 40 subject relative sentences; 40 object relative
sentences with and 40 object relative sentences without relative pronoun. In
Table 4.2, example sentences for each condition are given. All sentences had a
transitive action verb with NPs in singular form. There were 40 sets of pictures,
with each page consisting of a set of four different pictures.
Table 4.2: Examples of target sentences in the sentence-picture matching task.
Condition
Sentence types
Target sentence
in English
Target sentence
in Swahili
Base Order
Active
The man is
rescuing
the
woman
Point to the
man who is
rescuing
the
woman
Mwanamme
anamwokoa
mwanamke
Nionyeshe
mwanamme
ambaye
anamwokoa
mwanamke
Mwanamke
anaokolewa na
mwanamme
Nionyeshe
mwanamke
ambaye
mwanamme
anamwokoa
Nionyeshe
mwanamke
mwanamme
anamwokoa
Subject relative
Derived Order
Passive
Object relative
+ relative pronoun
The woman is
rescued by the
man
Point to the
woman who the
man is rescuing
Object relative
- relative pronoun
Point to the
woman the man
is rescuing
The tasks involved auditory sentence-picture matching. The participant
was shown a set of four pictures on one page and was asked to look at them all.
The examiner read a sentence aloud and asked the participant to point to the
picture matching the sentence (see 6 and Figure 4.1). One picture matched the
sentence and the three other pictures were distractors to help determine error
types: reversed role distractor, lexical distractor, and reversed role + lexical
distractor.
4.2. METHODS
101
Figure 4.1: An example of a set of pictures used in sentence-picture matching task taken
from the VAST (Bastiaanse et al., 2002).
(6)
Experimenter:
Mwanamme a-na-m-wokoa
mwanamke
Man
he/she-Present-him/her-rescue woman
‘The man is rescuing the woman’
The two languages were tested separately on two different days with an
interval of two weeks for each of the agrammatic individuals. The order of
the tests in each language was varied for each participant: either English first,
followed by Swahili or vice versa. To ensure the participants understood the
task before starting the test, each session began with ten practice items during
which corrections were allowed and feedback given. No further feedback was
given once the test began. Each session lasted two hours, with a break for the
102
CHAPTER 4. SENTENCE COMPREHENSION
agrammatic speakers. All the sessions were held in a speech therapy room at
the Aga Khan University Hospital in Nairobi, Kenya.
4.3
Results
The NBDs made no errors on either test. The results of the agrammatic speakers are shown in Table 4.3 and 4.4.
Table 4.3: The percentages correct of the agrammatic individuals on the Swahili test.
BASE ORDER
Subject
Actives
Relatives
EA
JN
SS
PN
MM
JA
MW
HJ
VK
HS
BM
Mean
100
100
100
100
100
100
98
100
100
100
100
99.8
95
95
100
93
100
100
98
100
100
100
100
98.3
DERIVED ORDER
Object
Object
Passives
Relatives+ Relatives63
68
85
60
80
63
55
78
80
68
63
69.4
40
60
55
40
68
58
58
73
63
53
53
56.5
60
53
33
40
68
53
63
70
58
50
50
54.4
In order to test the TDH, it was compared whether or not the agrammatic
individuals performed at chance level. Since virtually all errors (>95%) were
simple role reversals, chance level was set on 50%, 16,7% correct (33.3%66,7%). It can be seen from the tables that the TDH correctly predicts the
performance on most sentence types, but not on the passives in English, on
which the agrammatic individuals perform slightly above chance level. However, what the TDH ignores is the different level of performance between the
passives and the object relatives. An ANOVA was applied, to test for interaction effects between derived word order and embedding, as predicted by the
DOP-H.
We performed a repeated measures analysis of variance to investigate main
4.3. RESULTS
103
Table 4.4: The percentages correct of the agrammatic individuals on the English test.
BASE ORDER
Subject
Actives
Relatives
EA
JN
SS
PN
MM
JA
MW
HJ
VK
HS
BM
Mean
95
100
100
100
100
100
100
100
100
100
98
99.4
95
95
95
95
100
98
100
100
100
98
95
97.4
DERIVED ORDER
Object
Object
Passives
Relatives+ Relatives60
53
83
65
78
55
80
65
50
63
53
64.1
43
43
60
48
63
48
55
75
40
45
48
51.6
38
50
53
38
70
35
65
80
53
40
45
51.5
effects of language (English and Swahili), word order (base and derived) and
embedding (declaratives and relatives) on agrammatic performance. There
was no statistically significant effect for language (F (1, 10) = 2.882, p =.120:
Swahili and English were similarly affected. There was a statistically significant
main effect for word order: F (1, 10) =321.723, p =.000). Furthermore, there
was a statistically significant main effect for embedding: F (1, 1 0) = 23.056,
p =.001). There were no interaction effects for language x word order (F (1,
10) =1.996, p =.188) nor for language x embedding (F(1,10) =0.078, p =.786).
However, there was a significant interaction effect for word order x embedding
(F (1, 10)=19.207, p =.001). The interaction effect of word order x embedding
is graphically shown in Figure 4.2.
T-tests were performed to further explore the significant effects. Both in
Swahili and in English, there was a significant effect of argument order: performance on sentences with derived order was worse than on sentences with
base order of the arguments (Swahili: t (10) =17.86, p <.0001; English: t (10)
=14.26, p <.0001). Performance on embedded sentences (subject relatives and
both object relatives) was worse than on the declarative sentences (actives and
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CHAPTER 4. SENTENCE COMPREHENSION
100 100 80 80 60 60 40 40 20 20 0 0 base order Swahili simple derived order Swahili embedded base order English simple derived order English embedded Figure 4.2: Illustration of the interaction effects for order x embedding in Swahili and English.
passives) in both languages (Swahili: t (10) =7.054, p =.0002); English: t (10)
= 6.982; p =.0002).
Although there was no effect for language, we separately analyzed whether
the verb morphology interacts with comprehension. In Swahili, the passive
marker is part of the finite verb, whereas in English it is a preposition. This
morphological difference does not influence performance (t (10) =1.288, p
=.228).
4.3.1
Error analysis
The distribution of error types of the agrammatic speakers is presented in Table
4.5.
The agrammatic speakers pointed to each of the distracters, but not to
the same extent. Role reversal errors were the most prevalent in both Swahili
(95.7%) and English (96.8%). When agrammatic speakers heard sentences in
derived order condition (passive, object relatives with and without relative
pronoun), they most often pointed at the distracters in which the roles were
reversed. A few lexical errors were also noted in Swahili (4.1%) and in English
(2.7%) and a few errors that involved a combination of both role reversal and
lexical errors in Swahili (0.2%) and in English (0.5%).
In sum, the agrammatic individuals performed more poorly on sentences in
derived order condition than on those in base order condition and performance
diminished when another complex grammatical operation has to be performed
4.4. DISCUSSION
105
(embedding), as shown by the interaction effect. They make predominantly
role reversal errors in both languages when they fail to understand sentences
in derived order condition.
Table 4.5: Distribution of error types (raw scores) of agrammatic individuals in Swahili and
English tasks.
SWAHILI
Role Reversal Lexical
EA
JN
SS
PN
MM
JA
MW
HJ
VK
HS
BM
Mean
4.3.2
50
45
51
63
33
51
50
32
39
51
52
47.0
7
5
0
3
1
0
2
0
1
1
2
2.0
Other
0
0
0
1
0
0
0
0
0
0
0
0.1
ENGLISH
Role Reversal Lexical
64
63
40
61
36
64
54
32
63
59
62
54.4
4
0
3
1
0
2
1
0
0
3
3
1.5
Other
0
1
1
0
0
0
1
0
0
0
0
0.3
Swahili and English compared
Although the factor ‘language’ did not influence the performance, we looked
at the correlation between the scores on the two languages, to see whether the
agrammatic individuals are similarly affected in both languages. This is clearly
the case: there is a strong and significant correlation between their scores in
both languages: R = 0.92, p <.0001.
4.4
Discussion
The present study examined the comprehension of sentences with base and derived order of the arguments with and without embedding by bilingual agrammatic individuals. The results show that sentences in the derived order condition are more difficult to comprehend than those in base order and that there
is an interaction effect for embedding. A similar pattern of performance is
106
CHAPTER 4. SENTENCE COMPREHENSION
reflected in both languages, Swahili and English, irrespective of their morphological differences. This implies that the morphological differences in the verb
inflection system of the two languages do not play a role in comprehending
the sentences. We discuss these findings in relation to the theories of sentence
comprehension in agrammatism mentioned in the introduction.
4.4.1
The problems with derived order
Based on Grodzinsky and colleague’s (1995; 2006) TDH, the following predictions were made for the current study: (a) above chance level performance
for sentences in base order condition, actives and subject relative clauses, in
both languages; (b) chance level performance for sentences in derived order
condition, passives and object relatives with and without relative pronouns.
Although our test had 4 pictures, only one of the distractors was purely related
to word order and this was the picture chosen in the large majority of the errors.
We, therefore, assumed that chance level was 50% 16.67. In both Swahili and
English, the agrammatic individuals show good comprehension of both active
and subject relative sentences with scores ranging from 93% to 100%. On the
object relatives with and without relative pronoun, the scores are at chance
level. So far, the scores are in line with the TDH. On passives in Swahili,
however, the agrammatic individuals score above chance, which is incompatible with the TDH. The difference with chance level is not very large (69.4%),
this alone is not a reason to reject the TDH, because there is overwhelming
evidence that agrammatic individuals show around chance level performance
on sentences in which the arguments are not in canonical order (see Grodzinsky
et al., 1999). However, what the TDH does not predict is the interaction effect
between derived order of the arguments and embedding.
The DOP-H is a processing account that assumes worse performance when
the syntactic operations become more complex, but it is does not necessarily
predict performance at chance level. The specific predictions were that sentences with derived order of the arguments are harder to understand and that
embedding will further diminish performance, or, in terms of statistics, that
there is an interaction effect of word order and embedding. This is exactly
what has been found and this effect is largest in the derived order sentences.
That does not mean that sentences with embeddings in which the arguments
are in base order are processed faultlessly. It may very well be the case that
these sentences are also harder to process, but that application of a default
4.4. DISCUSSION
107
strategy results in almost perfect performance. On the basis of the current
data, we cannot exclude this possibility (but see Friedmann, 2008, who showed
that agrammatic individuals have problems understanding embedded sentences
without traces).
4.4.2
A working memory deficit?
Depending on how one would like to measure a WM deficit, different predictions
were considered in the Introduction, all of which are falsified by the data of
the current study. The short Swahili sentences are comprehended equally well
/ poor as those in English in all conditions. Filler - gap distance does not
play a role either: the object relatives with and without complementizer are
understood equally well. A WM-theory that assumes that the beginning and
end of the sentence are retained in memory, whereas the middle part is wiped
can account for the poor performance on the object relatives, but not on the
passives. If in the latter structure the middle part of the sentence, the verb, is
not available, lexical distractor pictures will be chosen, particularly those with
role reversal, since the first NP will be interpreted as the agent. However, on
the whole test by all agrammatic individuals, only 4 of these errors are made,
1 in Swahili and 3 in English. Also, lexical errors are expected for the subject
relatives that have the verb in the middle, although without role reversals,
because the first NP is the agent. In English in 1% and in Swahili in 0.5% of
the items, such a distractor picture was chosen. Therefore, we do not think
that a WM deficit can account for the data of the current study.
4.4.3
The effect of the morphological difference between
Swahili and English
In Swahili, the finite verb is very complex, encapsulating information about the
subject, the object, negation, time reference and, in passives, the finite verb
contains the passive marker. However, the language in which the agrammatic
individuals were tested did not influence their behaviour, implying that the verb
complexity does not contribute to their level of performance. This is interesting,
because another factor, embedding, does affect their comprehension. Hence,
the data suggest that performance, on a test where word order is a crucial clue
to understand the sentence, is influenced by structural complexity and not by
morphological complexity. That does not mean that their comprehension is
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CHAPTER 4. SENTENCE COMPREHENSION
not affected by verb morphology at all. From two previous studies (Abuom &
Bastiaanse, 2012; 2013), we know that Swahili-English bilingual agrammatic
individuals have problems with verb inflection when it is used for reference to
the past (‘he pushed’ is more difficult than ‘he is pushing’ and ‘he will push’) in
comprehension and in production in both languages. However, on the current
experiment, the morphological complexity of the Swahili verb paradigm did
not influence the agrammatic behaviour.
As in our earlier studies (Abuom & Bastiaanse, 2012; 2013), there is a strong
and significant correlation between the performance in both languages, meaning
that when the agrammatic individuals are poor in one construction in one language, they perform poorly in the other language as well. The same was found
in the present study, which is contrary to the assumption that a central underlying deficit in bilingual individuals with agrammatic Broca’s aphasia may cause
different surface manifestations in the languages that differ in their grammatical morphology (Paradis, 1988, Fabbro, 2001). Given that these agrammatic
speakers were early balanced bilinguals who acquired both languages early in
life and were equally proficient in both languages at the time of their aphasia
producing incident, we attribute their level of performance in both languages
to shared language processing brain regions for derived order sentences (e.g.,
Miozzo et al., 2010; Abutalebi et al., 2005).
In sum, in our group of bilingual agrammatic individuals, sentence comprehension is significantly hampered by derived word order. Embedding further
diminished their performance. The latter finding is not compatible with the
TDH, nor with any other representational theory. The DOP-H, that is very
similar in its assumption that derived order of the constituents is hard for
agrammatic individuals, is a processing theory. This means that the syntactic
representations in agrammatic aphasia are intact, but application of the linguistic operations to extract information from word order is impaired when word
order is derived. The present study demonstrates that the DOP-H makes correct prediction and also shows that application of another linguistic operation
(embedding) further reduces correct interpretation of the complex sentences.
CHAPTER
5
Sentence Production in Swahili-English bilingual
agrammatic speakers
Abstract
Background: It has been argued that agrammatic speakers’ production of sentences in derived order is impaired (The Derived Order Problem Hypothesis,
DOP-H), and that the underlying deficit in bilingual individuals with agrammatic Broca’s aphasia may cause different surface manifestations in the languages when they differ in terms of their grammatical morphology. The current study presents results of a study on sentence production in Swahili-English
bilingual agrammatic speakers. The two languages, Swahili and English, differ
significantly in terms of their verbal morphology.
Aims: The current study tested the production of sentences in base and
derived orders of arguments in the two languages of Swahili-English bilingual
agrammatic speakers.
Methods & procedures: Eight agrammatic and eight non-brain damaged
This study has been published online as:
Abuom, T. & Bastiaanse, R. (in press). Sentence production in Swahili-English bilingual
agrammatic speakers. Aphasiology. DOI:10.1080/02687038.2013.810328
109
110
CHAPTER 5. SENTENCE PRODUCTION
individuals participated in the study. A sentence elicitation test was used to
examine the production of sentences in base and derived word orders in Swahili
and English. The base order condition consisted of active and subject cleft
sentences, whereas the derived order condition tested passive and object cleft
sentences.
Outcomes & Results: The non-brain-damaged individuals performed at ceiling in both languages. The agrammatic speakers’ results, however, show sentences in derived order condition were more difficult to produce than those in
base order, similarly across the two languages irrespective of their morphological differences. Moreover, the embedded sentences were also more difficult to
produce than simple sentences for agrammatic speakers.
Conclusions: The current data partially support the DOP-H and provide
new insight into sentence production deficit of bilingual individuals with agrammatic Broca’s aphasia. The findings are discussed with respect to the theories
of sentence production in agrammatic speakers.
5.1
Introduction
Agrammatic speech production is generally characterized by problems with free
and bound grammatical morphemes (Goodglass, 1968; Caramazza and Berndt,
1985; Marshall, 1986), specifically with verb inflections for tense (Bastiaanse
& Jonkers, 1998; Bastiaanse, Hugen, Kos & Van Zonneveld, 2002; Friedmann
& Grodzinsky, 1997; Friedmann, 2000) and time reference (Bastiaanse, 2008;
Yarbay-Duman & Bastiaanse, 2009; Bastiaanse, Bamyaci, Hsu, Lee & Yarbay
Duman (2011). Apart from these problems with the production of grammatical
morphemes, syntactic deficits have also been described: verbs with complex argument structures (the Argument Structure Complexity Hypothesis (ASCH);
Thompson, 2003) and sentences in derived word order (the Derived Word Order Problem Hypothesis (DOP-H); Bastiaanse & Van Zonneveld, 2005) have
been demonstrated to be hard to produce in spontaneous speech (Thompson,
Shapiro & Schendel, 1995; Bastiaanse et al., 2002) as well as in sentence production tasks (Bastiaanse, Hugen, Kos & Van Zonneveld, 2002; Bastiaanse,
Koekkoek & Van Zonneveld, 2003; Bastiaanse & Thompson, 2003; Burchert,
Meiner & De Bleser, 2008; Yarbay Duman, Aygen, zgirgin, & Bastiaanse, 2007;
Yarbay Duman, Aygen & Bastiaanse, 2008). To this end, a number of linguistic
theories have been formulated to explain the source of agrammatic production
5.1. INTRODUCTION
111
problems (as discussed in the next section). However, all these theories are
based on data from monolingual agrammatic speakers. Paradis (1988) argues
that the same underlying deficit may cause different surface manifestations in
an aphasic bilingual individual when the languages differ largely in terms of
their grammatical morphology.
The current study was meant to test the Derived Order Problem Hypothesis
(DOP-H) on Swahili-English bilingual agrammatic speakers to determine the
pattern of impairment across the two morphologically different languages. In
the next section, we discuss some of the theories of agrammatic production,
followed by a description of Swahili word order. Then our previous studies on
Swahili-English bilingual agrammatic speakers will be discussed and we end
with the predictions of the current study.
5.1.1
Theories of sentence production
According to syntactic theories within the generative tradition (e.g., Chomsky, 1995; Pollock, 1989), when we produce and understand sentences, they
are represented as phrase structures known as syntactic trees. The highest
phrasal node in the tree is the complementizer phrase (CP), which hosts complementizers, which are embedding elements like “that”, and wh-morphemes
such as “where” and “what”. Thus, the construction of embedded sentences
or wh-questions, depends on the CP node being intact and accessible. Hagiwara (1995) was one of the first to claim that the top of the syntactic tree
was hard to access for agrammatic individuals (but see Ouhalla, 1993). In
1997, Friedmann and Grodzinsky reported the results of a single case study
of a Hebrew speaking agrammatic woman who showed dissociation between
tense and agreement morphology in her speech production: tense inflection
was impaired while agreement inflection was intact. The authors, by assuming
that tense and agreement are represented in separate nodes of the syntactic
tree where the tense node is located above the agreement node, as proposed
by Pollock (1989), proposed the Tree Pruning Hypothesis (TPH: Friedmann
and Grodzinsky, 1997) to account for this dissociation. The TPH claims that
the syntactic tree of agrammatic speakers is pruned and higher nodes (from
Tense node up, including the CP) are inaccessible. The consequence is that
agrammatic speakers are unable to project the syntactic tree up to its highest
nodes; hence, tense, wh-questions and embedded structures that require the
high nodes should be impaired.
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CHAPTER 5. SENTENCE PRODUCTION
However, the TPH has been challenged by data from several languages
based on verb inflection (e.g. Wenzlaff & Clahsen, 2004; 2005 and Burchert,
Swoboda, & De Bleser, 2005 for German; Stavrakaki & Kouvava, 2003 and
Nanousi, Masterson, Druks, & Atkinson, 2006 for Greek). Other studies showed
that it is not only the top of the syntactic tree that is inaccessible: operations
low in the syntactic tree are impaired as well (e.g. Bastiaanse et al., 2003;
Burchert et al., 2008).
Other key theories relate the agrammatic production difficulties to the complexity of sentence structures. Kim and Thompson’s (2000) study on English
agrammatic speakers’ production of one argument verbs (e.g. ‘to run’) with
two-place (e.g. ‘to read’) and three-place (‘to give’) verbs showed that threeplace verbs were more difficult to produce than two-place verb, which are more
difficult than the one place verb. A follow up study by Thompson (2003) on
agrammatic performance on unergative (e.g. ‘to sleep’) and unaccusative (e.g.
‘to fall’) verbs revealed a significantly better performance on unergative than
unaccusative verbs. To account for these data, Thompson (2003) provided the
Argument Structure Complexity Hypothesis (ASCH), attributing the sentence
production deficits in agrammatic aphasia to the complexity of the argument
structure of the verb: both the number of arguments and movement operations taking place at the surface level directly affect the ability to retrieve
verbs and to construct sentences. Bastiaanse and Van Zonneveld (2005) tested
the production of sentences with verbs with alternating transitivity, that is,
verbs that have a transitive and an unaccusative reading (e.g. to break: ‘he
breaks the glass’ vs ‘the glass breaks’) in Dutch agrammatic speakers. Agrammatic performance dropped significantly when sentences had to be produced
with unaccusative verbs that require derived word order, that is, that the theme
should be in subject position. Bastiaanse and Van Zonneveld (2005) interpreted
these results in terms of the Derived Order Problem Hypothesis (DOP-H). The
DOP-H is, although inspired by generative grammar, relatively theory-free. It
assumes that all languages have a base order and that all other word orders
are derived. The DOP-H predicts more problems for agrammatic speakers on
producing and comprehending sentences when constituents are in derived order than when they are in base order. It has been supported by production
studies in several languages. Bastiaanse et al. (2002a) reported that Dutch
agrammatic speakers showed greater difficulty with finite verb production in
the matrix clause (derived order) than embedded clause (base order). Basti-
5.1. INTRODUCTION
113
aanse and Thompson (2003) reported that English agrammatic speakers had
more problems with auxiliaries in yes/no questions (derived order) than auxiliaries in declarative sentences (base order). In recent studies involving object
scrambling (the grammatical object changes places with one of its adjacent
constituent, resulting in derived order; this is a frequent structure in Dutch,
German and Turkish, but it does not exist in English with its strict word
order), both Burchert et al. (2008) and Yarbay Duman et al. (2007; 2008)
reported that German and Turkish agrammatic speakers have more difficulties
producing sentences in which the object is in derived position. Interestingly,
Anjarningsih, Haryadi-Soebadi, Gofir, Bastiaanse (2012) found that agrammatic speakers of Standard Indonesian use a substantial number of passives
with derived order in their spontaneous speech, contrary to what the DOP-H
predicts. Anjarningsih et al. (2012) suggest that this can be explained by the
high frequency of passive sentences in Standard Indonesian. Passive sentences
are as frequent as, if not more frequent than, active constructions and the passive construction is the polite form to address people. Therefore the passive
construction is firmly anchored in the language system.
As mentioned, the DOP-H is an overarching theory that makes predictions
for both production and comprehension. Bastiaanse & Van Zonneveld (2006)
showed that it correctly predicts the performance on active and passive sentences in Dutch. However, there is more at stake in comprehension as two other
studies from our group have demonstrated. Yarbay Duman, zgirgin, Altιnok
& Bastiaanse (2011) tested comprehension of sentences with base and derived
order in Turkish agrammatic individuals. Turkish uses case to denote syntactic roles. In simple declarative sentences, the subject gets nominative case
and the object accusative case, but in structurally complex sentences, case assignment is marked. In object relatives, for example, the subject gets genitive
case and the object gets nominative case. The agrammatic individuals had
problems with derived order, as predicted by the DOP-H, but there was an
interaction effect with case assignment. Derived order sentences were harder
to comprehend when case assignment was marked. Similarly in our study on
Swahili-English sentence comprehension, Abuom, Shah & Bastiaanse, 2013),
the agrammatic individuals performed poorly on the sentences with derived
order of the arguments but there was an interaction with the factor embedding: subject relatives (base order of the arguments + embedding) were more
difficult than simple actives (base order of the arguments, - embedding), and
114
CHAPTER 5. SENTENCE PRODUCTION
object relatives (derived order of the arguments, + embedding) were more difficult than passives (derived order of the arguments, - embedding). This was
taken as support for a processing disorder that increases when more linguistic
operations are required. Processing derived word order is such an operation,
as well as embedding.
Many theories on agrammatism are primarily developed to describe the
problems with comprehension of semantically reversible sentences (e.g. the boy
is chased by the girl ), such as the trace deletion hypothesis (Grodzinsky, 1995;
2000) or the mapping theory (see, e.g. Linebarger, Schwartz & Saffran, 1983;
Schwartz, Linebarger, Saffran & Pate, 1987). The DOP-H has a larger domain:
it predicts agrammatic problems with, for example, verb position in Dutch
(Bastiaanse et al., 2002); auxiliaries in English yes-no questions (Bastiaanse
& Thompson, 2003), clitics in Italian (Rossi, 2007) and object scrambling in
Dutch (Bastiaanse et al., 2003) and German (Burchert et al., 2008).
The present study focuses on word order in Swahili-English bilingual agrammatic speakers. The emphasis is on the order of the arguments to enable testing
of the ‘overarching’ aspect of the DOP-H. In a previous study (Abuom et al.,
2013), comprehension of actives, passives and subject and object relatives has
been tested in this population. The current study uses similar sentence types.
Before formulating the predictions for this study, we describe some relevant
characteristics of Swahili grammar.
5.1.2
Swahili word order
Swahili is a Bantu language spoken mainly in Africa, including Kenya where all
participants in this study were drawn from. In Kenya, a multilingual society
where an average person speaks at least three languages, the two most dominant languages across the population are Swahili and English. Apart from
the two dominant languages, an average Kenyan uses one of the 42 native
languages that linguists term “ethnic languages” mostly at home with family members. Each of the 42 languages has been classified as Bantu, Nilotic,
Indo-Aryan or Cushitic. Swahili and English share the same status as second
languages since both are acquired around the age of 4, after native language
acquisition by the majority of Kenyans. Whereas Swahili is taught as one of
the subjects from kindergarten to university and also functions as the national
language and the language of politics, business, and daily interactions of people
from different ethnic backgrounds, English functions as the official language of
5.1. INTRODUCTION
115
instruction in all educational institutions from primary school to university,
and also as the language of news broadcasts, parliamentary proceedings, and
business. Therefore, a Kenyan with over 12 years of uninterrupted education
is generally expected to be equally and highly proficient in both languages.
Swahili is an agglutinative language, with a fairly fixed base word order
(SVO) at the sentence level, where the subject precedes the verb and the object,
see (1a) (Ashton, 1982). Usually, the agent is in subject position and the theme
in object position, like in English. Similarly, (1b) is a subject cleft sentence, a
structure that allows the speaker to emphasize the agent while maintaining the
base word order (agent - verb - theme). Other word orders are also possible
in Swahili. For example, in the passive sentence (2a), the theme is in subject
position in the sentence resulting to a derived order (theme - verb - agent). The
final vowel of the verb complex also changes from ‘-a’ to passive marker ‘-wa’.
As in English, the phrase ‘na’ (by) is included only if the information about
the agent is important for clarity purposes to the reader or the listener.14 In
an object cleft sentence (2b) the theme is in a position preceding the agent,
resulting in derived order of the arguments (theme - agent - verb).
(1)
(a)
Mama a-na-m-gonga
baba Ag-V-The15
Mother s/he-PRESENT-him/her-hit father
‘The mother is hitting the father’
(b)
Ni
mama ambaye a-na-m-gonga
baba Ag-V-Th
It is mother who
s/he-PRESENT-him/her-hit father
‘It is mother who is hitting the father’
(2)
(a)
14 In
Mama a-na-gong-wa
na kijana Th-V-Ag
Mother s/he-PRESENT-hit-PASSIVE by boy
‘The mother is hit by the boy’
both Swahili and English, the passive sentence is not simply an inversion of the
thematic roles, like in sentences with object scrambling: the verb morphology changes
into [auxiliary+participle], and the Subject NP becomes a PP (by-phrase). Theories on
how this derivation takes place differ largely. What is important for the current study
is the fact that he thematic roles are not in base order.
15 Ag=agent, V=verb, Th=theme
116
(b)
CHAPTER 5. SENTENCE PRODUCTION
Ni
baba
ambaye mama a-na-m-gonga Th-Ag-V
It is father who
mother s/he-PRESENT-him/her-hit
‘It is the father who the mother is hitting’
In both passive and object cleft sentences, operations have been applied
resulting in arguments that are no longer in their base position.
It is also clear from the examples (1-2) that the Swahili finite verb form is
more complex than that of English. It consists of several affixes which are both
inflectional and derivational morphemes, attached to the verb root. These affixes (prefixes and suffixes) must occupy specific positions and perform specific
functions. The general position scheme of the affixes in relation to the verb
root is shown in (3a). Some illustrations from Abuom, Obler & Bastiaanse
(2011) are given in (3b-d).
(3)
(a)
Pre-prefix (Pp) + Subject prefix (Sp) + Tense marker (T) + Object
prefix (Op) + ROOT + derivation (d) + Suffix (s) + Post-suffix (Ps).
(b)
A + li + m + gong
+ a
Sp + T + Op + ROOT + d
“S/he hit him/her”
(c)
Ha + tu + ta + m + gong
+ a
Pp + Sp + T + Op + ROOT + d
“We will not hit him/her”
(d)
Tu + na + gong
+ a + n + a
Sp + T + ROOT + d + S + Ps
“We are hitting each other”
The Swahili verb, unlike that of English, can function as a complete sentence. The verb paradigm consists of: subject prefix (subject-verb agreement),
tense marker (includes tense and aspect) and verb root, which are generally
obligatory in every grammatical Swahili sentence. However, the object prefix is
usually not obligatory when the object of the sentence is overtly present. The
subject prefix and object prefix must always agree in number with the subject
and the object of the sentence respectively, as illustrated in (1-2) above.
5.1. INTRODUCTION
5.1.3
117
Previous studies on Swahili-English bilingual
agrammatic speakers
Among the several theories of agrammatic production mentioned above, only a
few have been tested in bilingual speakers of structurally different languages to
determine whether the same underlying deficit may cause different surface manifestations in the different languages of a bilingual (Paradis, 1988). Abuom and
colleagues showed in several studies that Swahili-English agrammatic speakers
have a selective deficit for production and comprehension of verb forms that
refer to the past both in experimental settings (Abuom et al., 2011; Abuom
& Bastiaanse, 2013) and in spontaneous speech (Abuom & Bastiaanse, 2012).
Moreover, this impairment is more prominent in English with its relatively
simple verb inflection paradigm than in Swahili with its extensive, but entirely regular paradigm. These findings show that these agrammatic bilinguals
demonstrate the same pattern as agrammatic monolinguals (for an overview,
see, Bastiaanse et al., 2011 and Bastiaanse, 2013).
Having noted that Swahili-English agrammatic speakers, in the severity
range tested, have no problems with the present time frame constructions in
base word order, Abuom et al. (2013) tested their comprehension of present
time constructions in derived word order. We compared the comprehension of
sentences in two conditions: base order and derived order, in both languages
(Swahili and English). The results demonstrated that Swahili-English agrammatic speakers had greater difficulty comprehending derived order constructions (passive and object relative sentences) compared to base order conditions
(simple active and subject relative sentences). Furthermore, the performance
on both languages was strikingly similar irrespective of the morphological differences between the two languages. The findings are compatible with the
DOP-H. The DOP-H makes the same predictions for agrammatic comprehension and production, but so far, it has not been tested for similar constructions
in both modalities. Moreover, the participants of the current production study
are the same as those in the earlier comprehension study. This enables us to
analyze whether comprehension and production are affected to the same extent, a finding that would point to central deficit. A final unique point of the
current study is that the agrammatic speakers are early balanced bilinguals
who were tested in both languages.
118
5.1.4
CHAPTER 5. SENTENCE PRODUCTION
The current study
We tested the production of different sentence structures, in which two factors were varied: word order (base and derived) and sentence type (simple
declarative and embedding). Thus, we tested simple sentences with base and
derived order of the arguments (actives and passives, respectively) and sentences with embeddings in base and derived order (subject and object cleft
sentences, respectively). The DOP-H predicts more problems with the derived
order sentences. However, it is likely that, as in comprehension, the problems
increase when embedded sentences have to be produced. It is, therefore, predicted that subject clefts are more difficult than simple actives, although in
both sentence types the arguments are in base order and that object clefts are
more difficult than passives:
Active sentences > subject clefts ≥ passive sentences > object clefts.
It is unknown yet whether word order and embedding will have a similar complicating effect, making it unsure whether subject clefts will be more
difficult than or equally difficult as passives.
Studying these questions in a bilingual population enables us to evaluate
whether other factors further complicate sentence production and whether word
order and embedding are affected in the same way in two languages from two
different language families. As described above, the verb system in Swahili
is morphologically very extensive but also highly regular compared to English
verbs. Such a complex system requires further processing resources, and may
result in poorer performance in Swahili. It may also be the case that there will
exist qualitative difference in the responses in the two languages. Thus, it may
be that one language is more impaired than the other or that different error
patterns are observed.
5.2. METHODS
5.2
5.2.1
119
Methods
Participants
There were 16 participants in this study: 8 bilingual agrammatic speakers
of Swahili and English16,17 from the Aga Khan University hospital (Nairobi
Kenya) and 8 non-brain damaged bilingual speakers (NBDs). All were aged
between 26 and 51 years, with over 12 years of education. In 7 participants,
aphasia was caused by a stroke, in 1 by traumatic brain injury. The agrammatic
speakers were early balanced bilinguals equally proficient in English and Swahili
pre-morbidly, and none had any history of neurological, hearing or vision problems. The non-brain-damaged participants were matched to the agrammatic
speakers based on age, years of education, occupation and native language. Although there are no tests available to establish the aphasia syndrome in Kenya,
the aphasic speakers were assessed and diagnosed by neurologists as suffering
from aphasia. They were, further, judged by a speech therapist as agrammatic
in English based on their spontaneous speech production that was perceived
as being slow, effortful and ‘telegraphic’ (short phrases consisting of mainly
content words), but with relatively spared auditory comprehension of single
words on an adapted version of the BDAE-test (Boston Diagnostic Aphasia
Examination: Goodglass, Kaplan & Barresi, 2001). Their demographic details
and percentage scores on the test for auditory comprehension of words (on an
adapted version of the BDAE-test) in Swahili and English are given in table
5.1.
5.2.2
Materials & Procedure
A sentence production test for Swahili and English, developed using pictures
from Verb and Sentence Test (VAST; Bastiaanse et al., 2002; 2003) was used
to test whether word order, embedding and size of the verb inflection paradigm
(morphological complexity) influence sentence production differently in the two
languages of bilingual agrammatic speakers. The test in each language included
36 semantically reversible sentences distributed over two conditions: base order
and derived order. The base order consisted of: 9 simple active sentences (e.g.
16 The
8 agrammatic participants had previously participated in a study on sentence comprehension a year earlier (Abuom et al., 2013).
17 The term bilingual has been used in this study to refer to all those people who use two
or more languages or dialects in their everyday lives (Grosjean, 1994).
120
CHAPTER 5. SENTENCE PRODUCTION
Table 5.1: Details of the agrammatic participants and their scores (% correct) on the test
for auditory comprehension of words (on an adapted version of the BDAE-test)
in Swahili and English.
EA
JN
SS
PN
MM
MW
HJ
VK
Mean
Age
(years)
Gender
Handedness
Education
(years)
Years post
stroke/
head
trauma
Native
language
Swahili
BDAEsubtest
scores
English
BDAEsubtest
scores
43
51
31
37
48
51
46
26
41.63
M
F
F
F
F
F
F
F
R
R
R
R
R
R
R
R
16
13
12
14
16
16
14
16
14.63
18
11
18
2
11
2.5
11
3
9.56
Nilotic
Bantu
Indo-Aryan
Bantu
Nilotic
Bantu
Nilotic
Bantu
100
100
100
100
100
98.6
100
100
99.8
99
100
99
100
100
100
100
98.6
99.6
the man is rescuing the woman and 9 subject cleft sentences (e.g. it is the man
who is rescuing the woman) with embedding, but arguments in base order,
that is, the agent precedes the theme. For derived order, there were 9 passive
sentences (e.g. the woman is rescued by the man) with order of the arguments
derived, that is, the theme precedes the agent and is in subject position (and the
agent in the by-phrase), and 9 object cleft sentences (e.g. it is the woman who
the man is rescuing) with derived order of the arguments, the theme precedes
the agent, and an embedding.
The influence of size of the verb inflection paradigm was controlled by the
two languages that the agrammatic individuals speak: Swahili has an extensive
verb inflection paradigm that consists of the subject, object, tense, aspect and
passive markers (for passive sentences). In English the verb is only inflected
for tense and agreement
There were 36 pairs of pictures, a pair on each page, depicting the same
action but the agent in the first picture was the theme in the second and vice
versa. The infinitive of the verb was printed on top (see Table 5.2 for the
sentence types and Figure 5.1 for an example picture).
The pictures were shown to the participant who was asked to look at them
both. The experimenter named the people and animals in the pictures to ensure
proper recognition. He then constructed a sentence using the printed verb to
5.2. METHODS
121
describe the first picture and asked the participant to construct a sentence of
a similar structure to describe the second picture. For example, for Figure 5.1:
RESCUE
Figure 5.1: An example of a pair of pictures used in sentence production task (VAST: Bastiaanse et al., 2002).
Experimenter:
Participant:
(pointing to the picture on the left):
for this picture, you can say
“The woman is rescuing the man”
(pointing to the second picture on the right):
and for this picture, you can say...
“The man is rescuing the woman”
Four practice trials (one for each sentence type) preceded the experiment.
During the practice trials the participant got feedback and when needed, the
sentence was corrected and the participant was asked to repeat the correct
sentence, to ensure that the task was properly understood. No help was given
during the experiment and only neutral feedback was provided. There was no
time limit for participant’s response, and repetitions of the prompting sentence
were made as many times as requested. Self-corrections were allowed and only
the last answer was scored.
5.2.3
Scoring
All answers were transcribed in orthographic script and analyzed both quantitatively (correct / incorrect) and qualitatively (error analysis).
122
CHAPTER 5. SENTENCE PRODUCTION
Table 5.2: Examples of target sentences in the sentence production task
Sentence type
Target sentence in English
Target sentence in Swahili
Active
The man is rescuing
the woman
It is man who is
rescuing the the woman
The woman is rescued
by the man
It is the woman who
the man is rescuing
Mwanamme anamuokoa
mwanamke
Ni mwanamme ambaye
anamuokoa mwanamke
Mwanamke anaokolewa
na mwanamme
Ni mwanamke
ambaye mwanamme
anamuokoa
Subject cleft
Passive
Object cleft
5.3
Word order
Embedding
base
-
base
+
der.
-
der.
+
Results
There were no errors made by the NBDs on either test. The results of the
agrammatic speakers are shown in Tables 5.3 and 5.4.
Table 5.3: Individual agrammatic speakers’ correct raw scores on Swahili test
Agrammatic
participant
EA
JN
SS
PN
MM
MW
HJ
VK
mean
Actives
Subject
clefts
Passives
Object
clefts
Total
derived
order
max=18
Total
simple
Total
embedded
max=9
Total
base
order
max=18
max=9
max=9
max=9
7
9
9
9
9
9
8
9
8.6
2
3
7
6
5
3
5
7
4.8
4
4
6
3
5
3
5
5
4.4
max=18
max=18
0
2
3
2
4
1
5
4
2.6
9
12
16
15
14
12
13
16
13.4
4
6
9
5
9
4
10
9
7
11
13
15
12
14
12
13
14
13.3
2
5
10
8
9
4
10
11
7.4
A repeated measures analysis of variance was performed to investigate main
effects of language (English and Swahili), word order (base and derived) and
embedding (simple and embedded) on agrammatic performance. There was a
significant effect for language: F (1, 7) = 8.430, p = .023, word order: F (1, 7)
= 149.075, p < .000, and embedding: F (1, 7) = 62.906, p < .000. There were
no interaction effects for language x word order (F (1, 7) =0.023, p =.885),
nor for language x embedding (F (1, 7) = 0.955, p =.361) (see Figure 5.2).
5.3. RESULTS
123
Table 5.4: Individual agrammatic speakers’ correct raw scores on English test
Agrammatic
participant
EA
JN
SS
PN
MM
MW
HJ
VK
mean
Actives
Subject
clefts
Passives
Object
clefts
Total
derived
order
max=18
Total
simple
Total
embedded
max=9
Total
base
order
max=18
max=9
max=9
max=9
5
9
8
9
8
9
6
9
7.9
2
2
7
3
4
3
5
5
3.9
3
3
5
4
5
5
4
3
4
max=18
max=18
0
1
3
2
0
2
2
2
1.5
7
11
15
12
12
12
11
14
11.8
3
4
8
6
5
7
6
5
5.5
8
12
13
13
13
14
10
12
11.9
2
3
10
5
4
5
7
7
5.4
However, there is a significant interaction effect for word order x embedding (F
(1, 7) = 8.188, p = .024). Overall there is no interaction for: language x word
order x embedding (F (1, 7) = 0.549, p = .483).
We performed t-tests to explore the significant effects further. The agrammatic speakers performed significantly poorer in English than in Swahili (t (7)
= 2.903, p = 0.0270). They also showed significant difficulty producing sentences in derived order compared to those in base order condition (Swahili: t(7)
= 8.450, p < .0001; English: t(7) = 11.180, p < .0001); They performed poorly
on passives compared to active sentences (Swahili: t(7) = 9.379, p < .0001;
English: t(7) = 6.675, p < .0001), and worse on object clefts than subject clefts
(Swahili: t(7) = 4.123, p = .004; English: t(7) = 5.158, p = .001). Finally,
the performance on embedded sentences (subject clefts and object clefts) was
worse than on the declarative sentences (actives and passives) in both languages
(Swahili: t(7) = 6.666, p <.0001; English: t(7) = 7.021; p < .0001).
5.3.1
Error types
The distribution of error types of the agrammatic speakers is presented in
Tables 5.5 & 5.6.
Errors produced by the agrammatic speakers were distinguished into four
categories: word order (when the arguments are not in the correct position:
“The man is rescuing the woman” Target: “The woman is rescued by the
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CHAPTER 5. SENTENCE PRODUCTION
9 9 8 8 7 7 6 6 5 5 4 4 3 3 2 2 1 1 0 0 base order derived order simple base order embedded simple derived order embedded Figure 5.2: Illustration of the interaction effects for word order x embedding in Swahili and
English
Table 5.5: Individual agrammatic speakers’ distribution of error types (raw scores) on Swahili
task.
EA
JN
SS
PN
MM
MW
HJ
VK
mean
Word
order
Embedding
Word order &
embedding
Others: repetition
of given verb form
5
5
3
6
4
6
4
4
4.6
7
6
2
3
4
6
4
2
4.3
9
7
6
7
5
8
4
5
6.4
2
0
0
0
0
0
1
0
0.4
man”), embedding (when the relative marker ‘who’ or ‘ambaye’ is omitted’ in
the sentence: “the man is hitting the woman” Target: “It is the man who
is hitting the woman”) both word order and embedding (when the sentence
produced is the reverse of the target sentence and the relative marker is missing:
“The man is guarding the woman” Target: “It is the woman who the man
5.3. RESULTS
125
Table 5.6: Individual agrammatic speakers’ distribution of error types (raw scores) on English
task.
EA
JN
SS
PN
MM
MW
HJ
VK
mean
Word
order
Embedding
Word order &
embedding
Others: omissions
of ‘is’; repetition of
given verb form
6
6
4
5
4
4
5
6
5
7
7
2
6
5
6
4
4
5.1
9
8
6
7
9
7
7
7
7.5
4
0
1
0
1
0
3
0
1.1
is guarding”), other (repetition of the given form of the verb: “*Man rescue
woman” , omission of ‘is’ for English: “*Man rescuing woman”). Errors of word
order and embedding combined occurred equally often in Swahili and English
(t (7) = 1.843; p = .108). Other errors, such as repetition of the given verb
form in both languages and the omission of ‘is’ in English, hardly occurred.
In sum, the results show that Swahili-English agrammatic speakers have
more problems producing sentences in derived order - passives and object cleft
constructions - than in base order condition. However, within both orders, base
and derived, the embedded variant is more difficult than the variant with simple
sentence structures. The most common errors are production of sentences with
arguments in base position where derived orders was required and of sentences
without embedding in the embedded condition. In object clefts both the order
and the embedding were often avoided. These findings imply that it is not only
the derived order that is a problem to agrammatic speakers, but also embedded
constructions.
126
5.3.2
CHAPTER 5. SENTENCE PRODUCTION
Swahili and English compared
The Swahili version of the test was easier for the agrammatic speakers than
the English version. In order to find out whether the grammatical disorder
influences word order and embedding in Swahili and English in the same way,
the correlation between the scores in the two languages was calculated. The
results show that a common underlying impairment is very likely: there is a
strong and significant correlation between the scores in the two languages (R =
.885, p <.0001). Notice that performance is better in Swahili than in English,
despite the larger verb inflection paradigm in Swahili. We will come back to
this in the Discussion.
5.3.3
Production and comprehension compared
The DOP-H aims to be an overarching theory and has been supported in several
studies with production and comprehension data, however, never in the same
population. In order to claim a theory to be overarching, the same structures
should be impaired to the same degree in the same individuals. To test this,
correlations between comprehension and production were calculated. Each of
the 8 agrammatic speakers of the current study participated in the comprehension study as well. There is a strong and significant correlation between the
production and comprehension scores, both in Swahili (R =. 759, p < .0001
and in English (R = .692, p < .0001).
5.4
Discussion
The primary goal of the current study was to test the DOP-H, which predicts
difficulty in production of derived order sentences by the agrammatic speakers.
However, an interaction with linguistic complexity other than word order was
found. Moreover, by testing bilingual agrammatic speakers of two structurally
different languages, we were able to measure whether the size of the verb inflection paradigm played a role. Finally, by comparing the data with those on
a similar comprehension test, the overarching aspect of the DOP-H could be
tested.
5.4. DISCUSSION
5.4.1
127
The DOP-H and linguistic complexity
The data show that Swahili-English bilingual agrammatic speakers’ performance on sentence production is affected by word order. Sentences with base
word order are produced better than those with derived word order: relatively few errors were made on active and subject cleft sentences compared to
passive and object cleft sentences, respectively. This is exactly what the DOPH predicts. Several studies on production involving monolingual agrammatic
speakers have supported this hypothesis as well: Bastiaanse et al., (2002a) for
Dutch; Bastiaanse and Thompson (2003) for English; Burchert et al. (2008)
for German; and Yarbay Duman et al. (2007; 2008) for Turkish. However,
two comprehension studies showed that the DOP-H alone does not sufficiently
predict the observed patterns. When statistical comparisons are made it is evident that there is an interaction between derived word order and other levels
of linguistic complexity. Yarbay Duman et al. (2011) showed that for Turkish agrammatic individuals derived order sentences are hard to interpret, and
within the derived order structures, there is also a hierarchy. Performance on
derived order sentences with unmarked case assignment (subject nominative
case and object accusative case, as in sentences with object scrambling) is better than when case assignment is marked (subject genitive case and object
nominative case, as in Turkish object relative sentences). A similar interaction
effect was reported by Abuom et al. (2013) for comprehension in SwahiliEnglish bilingual agrammatic individuals. Derived order sentences were harder
to comprehend than base order sentences, but there was an interaction with
embedding. For both languages, the order of difficulty was: simple actives >
subject relatives > passives > object relatives. The same is observed in the
present study on agrammatic production (for the same individuals who were
tested on comprehension). Derived order is indeed a problem, but embedding is
as well and sentences with both derived word order and embedding are hardest
to produce: simple actives > subject clefts > passives > object clefts.
The error analysis showed that in both languages, the agrammatic speakers frequently omitted the relative pronoun ‘who’ in English and ‘ambaye’ in
Swahili suggesting a general difficulty in producing embedded clauses. This
is an aspect that is not included in the DOP-H. The question is why embeddings are difficult. Of course, embedding is a difficult operation that is usually
introduced by a complementizer. The complementizer itself, being a function
word, may be the problem. However, if it is the production of the function
128
CHAPTER 5. SENTENCE PRODUCTION
word, rather than the linguistic operation, that is difficult, then one expects
agrammatic speakers to produce embedded sentences in which optional complementizers are omitted (such as ‘I think he will come home’ and ‘the boy
reading the newspaper is absent-minded’). However, agrammatic spontaneous
speech data show that hardly any embeddings are produced, suggesting that it
is embedding that is the problem, rather than the production of the complementizer per se. (see, e.g. Abuom & Bastiaanse, 2012, for data on Swahili-English
agrammatic spontaneous speech, Bastiaanse et al., 2002a , for Dutch spontaneous speech and Saffran, Berndt & Schwartz, 1989, for English spontaneous
speech).
The problem with embedding in agrammatic speech production is a robust
phenomenon that has previously been reported in several studies in aphasiology literature. Data from spontaneous speech in various languages show that
agrammatic speakers have severe difficulties with the production of embedded
sentences which manifest in their avoidance of complex sentences and in errors
they make when they try to produce them. This was reported for English
(Thompson et al., 1996, 1997; Bates, Friederici, Wulfeck, & Juarez, 1988),
for Italian and German (Bates et al., 1988), French (Nespoulous, et al. 1988;
1990), Japanese, (Hagiwara, 1995) and Dutch, Swedish, Polish, and Finnish in
Menn and Obler’s (1990) corpora. The theory of Hagiwara (1995) and the TPH
Friedmann and Grodzinsky, 1997) attribute this difficulty to a pruned syntactic from the T node up, including the CP, in agrammatic speakers’ syntactic
representation. Since the relatives ‘who’ and ‘ambaye’ are in complementizers,
the TPH correctly predicts these omissions. When the TPH assumes that the
subject of a passive sentence is in the specifier of the complementizer phrase,
it can also explain the problems with passive sentences. However, the TPH is
not an adequate alternative to explain the current data. First, the TPH does
not predict that object clefts are more difficult than subject clefts. Second,
the TPH predicts tense problems and the agrammatic speakers in the current
study did not make one single tense error. The TPH, therefore, partly explains
the problem with embedded structures observed in the current data, but it
does not account for the difficulties with derived order sentences.
We, thus, conclude that both the DOP-H and the TPH can only account
partly for the current data. While the DOP-H explains the difficulty with
derived order sentences, the TPH can account for the difficulty with embedded
structures. A unifying theory that can combine both problems is still lacking.
5.4. DISCUSSION
5.4.2
129
Production in Swahili and English
One of the questions was whether the extensive Swahili verb forms would result
in poor performance compared to the relatively simple English verb forms we
used. We deliberately used those forms that were most accurately produced in
an earlier study (Abuom & Bastiaanse, 2012; 2013) on time reference: present
imperfect for Swahili and the gerund for English. In these studies, the same
pattern was observed as in the current study: performance in Swahili, with its
extensive verb morphology, was significantly better than in English. Hence, we
can conclude that the complexity of the verb form does not influence production. However, like in two studies on time reference through verb inflection and
in the study of Abuom et al. (2011), performance was better in Swahili. Given
the relatively poor but irregular morphological system of English in contrast
with the stronger and more regular system in Swahili, the current finding is in
line with Menn and Obler (1990). They suggest that in languages with a small
paradigmatic system (such as Swahili) fewer errors in grammatical morphology
are made than in languages with a broader range of choices within the paradigm
(such as English. It cannot be excluded, of course, that the agrammatic speakers are (all) more proficient in English than in Swahili. However, this is quite
unlikely, because both languages are used on a daily basis, both before and after
the brain damage. An alternative explanation is that embedding and derived
word order are more frequent in Swahili than in English. Such frequency counts
are not available for Swahili. However, in our spontaneous speech study, both
the bilingual non-brain-damaged and the bilingual agrammatic speakers used
more embedded sentences in English than in Swahili (Abuom & Bastiaanse,
2012). Also, Bastiaanse, Bouma and Post (2009) showed that the frequency
of sentence structures does not influence agrammatic performance. In Dutch,
for example, the order Subject - Verb - Object is 50% more frequent than the
structure Subject - Object - Verb. However, agrammatic speakers are significantly better in producing the latter order, which is the base order in Dutch.
SVO is, despite being more frequent, derived.
However, the similar pattern of performance across the two languages irrespective of their morphological differences, even though Swahili appears slightly
better preserved than English, suggests one central deficit underlying the general performance patterns.
130
5.4.3
CHAPTER 5. SENTENCE PRODUCTION
DOP-H: an overarching processing theory
As mentioned in the introduction, DOP-H is an overarching theory predicting
more problems for agrammatic speakers on both production and comprehension
of sentences whose arguments are in derived position. It has been supported
by not only production studies in several languages (Bastiaanse et al., 2002a;
Bastiaanse and Thompson, 2003; Burchert et al., 2008; and Yarbay Duman
et al., 2007; 2008) but also several comprehension studies (Bastiaanse & Van
Zonneveld, 2006); Yarbay Duman et al., 2011). The current data on production
as well as the previous finding on comprehension study of bilingual agrammatic
speakers (Abuom et al., 2013) further support this theory; and provide new
insight into sentence production deficit of bilingual individuals with agrammatic
Broca’s aphasia. However, DOP-H does not cover problems with embedding
also found in the current study.
CHAPTER
6
General Discussion and Conclusion
This chapter presents a general discussion and conclusion of the previous
chapters of the thesis. In recap, this thesis project investigated the patterns
and severity of verb inflection and word-order production and comprehension
deficits in Swahili-English bilingual agrammatic speakers in light of several
theories of agrammatism. Through a set of behavioral off-line testing techniques -a spontaneous speech elicitation task, a sentence completion task, a
sentence-picture matching task, and a sentence production elicitation task–
the four studies presented in the previous chapters examined how some of the
theories, widely tested among monolinguals, apply to bilingual agrammatic
speakers. Furthermore, the universality of these theories in relation to Swahili,
a highly agglutinative Bantu language with a complex verb inflection paradigm
when compared to most languages studied so far, has also been determined.
The results demonstrated significant effects of time reference, word order and
embedding (wh-movement) on the performance patterns of bilingual agrammatic speakers across their two languages. Swahili-English bilingual agrammatic speakers were compromised in their verb use in spontaneous speech, and
in their production and comprehension of time reference to the past through
verb inflection and derived word orders. Although some of these phenomena
131
132
CHAPTER 6. DISCUSSION AND CONCLUSION
have been mentioned before, there are several novel findings: (1) these studies have been performed in Swahili, a language in which aphasia has not been
studied before; (2) systematic group studies on agrammatic comprehension and
production have not been done before in a bilingual population; (3) most interesting, some of the agrammatic speakers participated in both the time reference
and the word order and embedding studies on comprehension and production.
So far, the problems with time reference, word order and embedding have not
been studied in the same individuals before.
In this section: first, we highlight the major findings and address major
issues arising from the studies in relation to the literature presented in the
Introduction. Second, we discuss some of the clinical implications of the study.
Finally, we provide some recommendations for future research.
6.1
Major research findings
There are five major findings from the studies presented in this thesis: (1)
the agrammatic spontaneous speech in Swahili is not fundamentally different
from agrammatic speech in English; (2) time reference to the past through verb
inflection is impaired in production and comprehension in both languages as
predicted by the PADILIH, but more seriously in English than in Swahili; (3)
both production and comprehension of sentences with derived word orders are
impaired, as predicted by the DOP-H; (4) the comprehension and production is
influenced by embedding; (5) the agrammatic performance in both languages
is very similar. The individual research questions as formulated in the final
section of the Introduction have already been addressed in the separate research
chapters (2-5). In this discussion, some major issues that were presented in the
Introduction or which arose in the studies will be addressed.
6.1.1
Language dependent variables in spontaneous speech
As shown in the Introduction and other sections of the thesis, there are remarkable structural (morphological) differences between Swahili and English.
Swahili, being an agglitunative language, conveys more information in fewer
words than in English. Initial analysis of NBDs samples showed that information conveyed in 3 words in English is generally conveyed in 2 words or less
in Swahili. It is, therefore, logical that analysis based on equally sized lan-
6.1. MAJOR RESEARCH FINDINGS
133
guage samples was not appropriate for cross-linguistic comparisons. Brodshire
and Nicholas (1994) point out that a minimum of 300 words is a reliable sample size for analysis for languages such as English, but that in agglutinative
languages, fewer words can be used, especially when a comparison with spontaneous speech in a non-agglutinative language has to be made. Based on this
argument we analysed 300 words for English and 200 words for Swahili. Our
comparisons of Swahili and English agrammatic speech samples did not reveal
any fundamental differences between the two languages, especially in variables
that were not expected to yield any differences. Of course, the utterances of the
Swahili samples, both of the agrammatic and the non-brain-damaged speakers,
were about one third shorter than in the English samples. In both languages,
a considerable reduction in utterance length, a delay in speech rate, use of
verbs and nouns (whose ratio is, surprisingly, the same as that of controls),
production of more ungrammatical sentences and production of fewer embedded sentences was observed when the agrammatic samples were compared to
those of non-brain-damaged speakers.
Interestingly, a comparison of Kenyan English speech samples with those
of American English, which we did to determine whether analysis of spontaneous speech in languages for which aphasia tests are not available is sufficient
to identify agrammatism, also showed similar manifestation of agrammatism
in the two groups (monolinguals and bilinguals), irrespective of the number
of languages mastered pre-morbidly. This implies that it is not always the
case that agrammatism manifests differently in languages that differ in terms
of their grammatical morphology, as argued by Paradis (1988), but it shows
that the general characteristics of agrammatism are universal with only minor
differences in specific junctures where the two languages differ (Fabbro, 2001),
at least in aphasic individuals who are agrammatic in both languages. In our
data, minor differences were found upon further analyses of the use of verb inflections in both languages. Grodzinsky (1991) and Paradis (1995) predict that
agrammatic individuals will omit grammatical inflections in languages that allow bare forms, but will substitute them in languages where omissions result
in non-words. Indeed, there were some differences in patterns of omissions and
substitutions of grammatical morphemes not only in support of Fabbro (2001),
but also of Grodzinsky (1991) and Paradis (1995). In Swahili, the agrammatic
individuals substituted the finite verb forms with non-finite verb forms by using forms with ku- (infinitive marker) and ka- (consecutive marker) more often
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CHAPTER 6. DISCUSSION AND CONCLUSION
than normal. For English, the agrammatic speakers overused the infinitive (by
omission of the tense inflection) and the gerund forms of lexical verbs. However, in both languages the agrammatic speakers had a clear preference for verb
forms (both tense and aspect) referring to the present rather than to the past.
We interpreted the use of fewer verb forms that refer to the past as pointing to
an underlying selective deficit for verb forms referring to the past as predicted
by the PADILIH.
6.1.2
Representation vs. processing
In the Introduction, several linguistic theories of agrammatism, both processing
and representational accounts, were highlighted and their relevance to each
of the studies was discussed in detail. The TPH (Friedmann & Grodzinsky,
1997) is a representational account; the TUH (Wenzlaff & Clahsen, 2005) and
TAUH (Burchert et al., 2005) are both processing accounts. But all three
predict agrammatic speakers’ production difficulties with tense in general. The
PADILIH (Bastiaanse et al., 2011), a processing account, finds this prediction
to be both too narrow and too broad. According to the PADILIH, it is narrow
in the sense that the deficit is not restricted to tensed verb forms but also
holds for other verb forms expressing time reference through aspect inflection
and through periphrastic verb forms, and it is broad because not all tenses are
equally affected: present and future tenses are relatively spared. Our data from
the spontaneous speech analysis (Chapter 2) and time reference study (Chapter
3) showed an impaired production and comprehension of verb forms for time
reference to the past in both languages. This further supports the PADILIH,
expanding it to include bilingual agrammatic speakers’ data as well.
The PADILIH, in addressing the question of why reference to the past is
impaired, bases its argument on Avrutin’s discourse linking theory, also a processing theory. Avrutin (2006) attributes the agrammatic speakers’ difficulty
with tense to discourse linking, which he argues is impaired in agrammatic
aphasia. In distinguishing two levels of syntax processing, sentence level versus discourse level, Avrutin argues that because of brain damage, agrammatic
speakers do not have sufficient processing resources required for syntactic processing at the discourse level. He does not mention that one specific tense is
affected. Zagona (2003) clarifies that only past tense is affected since it requires
discourse linking, whereas both present and future tenses do not need such linking. She argues that when referring to the past, speech time and event time do
6.1. MAJOR RESEARCH FINDINGS
135
not coincide, hence, a discourse linked relation has to be made between speech
time and an earlier event. Bastiaanse and colleagues (2011), in formulating
PADILIH, extended Zagona’s theory on discourse linking to include reference
to the past through grammatical morphology in general.
Another set of theories, the TDH (Grodzinsky, 1986), a representational
account, and the DOP-H (Bastiaanse & Van Zonneveld, 2005), a processing
account, focus mainly on the order of constituents in a sentence. Whereas
the TDH predicts agrammatic speakers’ problems only with comprehension of
sentences whose arguments are in non-canonical order, the DOP-H makes similar predictions for both production and comprehension. Our data on sentence
comprehension (Chapter 4) supported both theories, while the data on sentence production (Chapter 5) supported the DOP-H. Although these theories
have initially been developed on the basis of the performance of monolingual
agrammatic speakers, their predictions can now be extended to include bilingual agrammatic speakers in both their languages.
Interestingly, these studies on the effect of word order included base and
derived order sentences with and without embedding. Although it is wellknown that agrammatic speakers are very limited in their use of embedded
sentences (e.g. Bastiaanse et al., 2002), it has not been shown before that
embedding is impaired in both production and comprehension and that there
is an interaction between embedding and word order in agrammatic aphasia.
Apparently, time reference to the past, derived order of arguments and
embedding compromise both production and comprehension of agrammatic
speakers, irrespective of language or number of languages pre-morbidly mastered. These data do not fully support representational deficit accounts, which
attribute the agrammatic speakers’ problems with speech production and comprehension to a complete lack (loss) of linguistic representation. The fact that
the agrammatic participants were able to produce and comprehend simple sentences in present tense and in base word order perfectly well, as well as a few
sentences in past tense and derived word orders, shows an intact grammatical
representation. Processing deficit accounts can fully account for these data.
The agrammatic speakers’ abilities to process discourse linked elements (reference to the past) as well as complex structures (derived word orders and
embedded sentences) were seriously affected, but not completely absent.
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6.1.3
CHAPTER 6. DISCUSSION AND CONCLUSION
Bilingual aphasia and the bilingual brain
As mentioned in the current studies, the agrammatic participants were balanced bilinguals who were premorbidly equally proficient in Swahili and English, having acquired both languages at an early age (4 years old) and another (native) language from birth. Although the two languages in question
are morphologically different (rich vs. poor morphology), the performance of
agrammatic individuals across the two languages in all the studies is either
similar or slightly better in Swahili. The similarity in performance across the
two languages, irrespective of the differences in grammatical morphology, implies that the agrammatic individuals suffered from the same type of aphasia
in both languages. They were not only agrammatic in both languages, but the
degree of their agrammatism was equally severe as shown by the high correlations between performance in Swahili and English, and between production
and comprehension tasks. Therefore, it is unlikely that the two grammars,
no matter how different they may be, are represented in different areas of the
brain (or separate neuroanatomical representations for the two languages, as
suggested by Albert and Obler, 1978). It has, however, been assumed that languages that are acquired early are generally represented in shared processing
regions of the brain in early balanced and proficient bilinguals (Miozzo et al.,
2010; Abutalebi et al., 2005). Therefore, what these results suggest is that the
syntactic representations of the two languages may not have been affected due
to brain damage (no patient scored a zero on all tests), but that processing is
impaired; that is, complex syntactic operations are hard to handle but apparently these operations take place in one and the same area for both languages.
This area is probably in the vicinity of Broca’s area because this area is known
to be crucial for linguistic processing and is often damaged or not functioning
properly in agrammatic Broca’s aphasia. Apparently, the damage to Broca’s
area affects both languages equally.
6.2
The clinical implications of the results of
this study
These research findings have implications for the diagnosis and treatment of
Swahili-English bilinguals with agrammatism. One of the key findings is that
both languages are similarly affected, irrespective of their morphological differ-
6.2. CLINICAL IMPLICATIONS
137
ences. The question, therefore, is whether it is sufficient to test and treat only
one of the languages or all languages known by the patient. This has been a
great challenge for speech therapists in Kenya who are mostly foreigners who
can only conduct therapy sessions in English. Paradis (1995) argues that it is
not ‘ethically accepatable’ for speech therapists to assess bilingual patients by
examining only one of their languages. This argument has been supported by
Fabbro (1990) who adds that it is wrong for clinicians to ignore the principles
of bilingual aphasia when it comes to the diagnosis of and therapy for language disorders. The current study, however, shows that this is not necessarily
the case. All of our patients were examined and treated in English, but their
Swahili was equally, if not less, impaired. It is conceivable that treatment in
English enhanced performance in Swahili, but as records of treatment were not
kept and no pre- and post-treatment testing systematically undertaken, one
cannot know. Cross-language generalization of treatment has been reported
before. Edmonds and Kiran (2006) found cross-language generalization after
lexical training when the non-treated language was the speaker’s more dominant language or when the participants were highly proficient in both their
languages. Similarly, Goral, Levy and Kastl (2010), who treated a patient
at the grammatical level in English (L2), found improvement in speech rate
and morphosyntactic skills in the treated language, English (L2), as well as
in non-treated French (L3). It is, therefore, evident that not only the treated
language but also the non-treated language can benefit from therapy. Thus, it
is important for the clinician to decide which language to treat depending on
the level of language dominancy or proficiency prior to brain damage.
Other specific findings are that the patients in the current study have difficulties producing and comprehending sentences referring to a past time-frame,
as well as those whose order of arguments are derived (in both Swahili and
English). It is, therefore, recommendable for therapy purposes that bilingual
individuals with agrammatism are explicitly instructed using simple sentence
structures in order to improve their communicative abilities. With respect to
treatment, some studies suggest that the type of syntactic movement, whether
NP- or Wh- movement, is an important factor to consider for aphasic individuals with sentence deficits. For instance, Thompson and colleagues provide
evidence from a series of studies that show that training sentences with Whmovement, such as object relative clauses, does not influence production or
comprehension of sentences with NP-movement, such as passives, though gen-
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CHAPTER 6. DISCUSSION AND CONCLUSION
eralization across sentences with similar movement operations has often been
observed (e.g., from object relative structures to object Wh-question forms)
(Dickey & Thompson, 2007; Thompson, Choy, Holland & Cole, 2010; Thompson & Shapiro, 2005; Thompson, Shapiro, Kiran & Sobecks, 2003). The tests
used in word order experiments are associated with both types of syntactic
operations: NP-movement (i.e., passives) and Wh-movement (i.e., object clefts
and object relative clauses) in both production and comprehension tasks.
In conclusion, like in the case of monolinguals, we can safely assume that
verb and word order deficits are prevalent in bilingual individuals with aphasia. Tests for these deficits are needed in order to understand the extent of
patients’ language impairment and for treatment planning. However, there are
no relevant and appropriate test batteries for bilingual aphasia that can address the aforementioned deficits. The tests used in several chapters of this
study provide a comprehensive assessment tool that can conveniently be used
by both clinicians and speech therapists for purposes of screening agrammatic
speech and therapy interventions.
6.3
Scope for further study/research
In future research, it would be interesting to examine Swahili-English bilingual speakers with fluent aphasia, such as Wernicke’s aphasia and anomia.
Furthermore, it would be interesting to test some of the native languages of
Kenyan bilingual aphasic speakers, to see whether the patterns of impairments
in Swahili and English are reflected in their native languages. Finally, while
it was beyond the scope of this study to show if there is a relation between
time reference and word order deficits, future research may aim at a common
underlying deficit.
Summary
This thesis focused on the manifestation of agrammatism in Swahili-English
bilingual speakers with aphasia, by investigating verb inflection and word order deficits in light of several theories of agrammatism. Whether, and to what
extent, some of the linguistic theories of agrammatism apply to bilingual agrammatic speakers of Swahili and English has been extensively addressed in the
four study chapters of this thesis.
The first study, presented in Chapter 2, aimed to identify the features of
Swahili agrammatic narrative and spontaneous speech, and to compare the
use of verb inflections for tense and time reference (in Swahili and English)
of the agrammatic and non-brain-damaged individuals by addressing three
main research questions. The first question was to determine whether there
are similarities or differences in the English speech production of monolingual
American and bilingual Kenyan aphasic speakers. The reason for this question was to establish whether the analysis of the spontaneous speech of aphasic
speakers in languages for which there are no standardized tests (for instance,
languages spoken in Kenya) is sufficient to identify agrammatism. The results
showed a remarkable similarity between agrammatic phenomena by monolingual American and bilingual Kenyan speakers on typical agrammatic features:
utterance length and speech rate are reduced, and the proportion of grammatical sentences and complex sentences is lower than normal. The second question
sought to establish the features of Swahili agrammatism and describe how comparable they are to features of English agrammatism. Having established that
the aphasic participants were agrammatic in English, additional analyses were
done in Swahili and comparisons were made with the English samples. As
expected, the Swahili agrammatic samples, when compared to those of non-
139
140
SUMMARY
brain-damaged individuals showed features that generally quantify agrammatism: reduced speech output; low speech rate; shorter utterances; limited use of
embeddings in sentences; and frequent production of ungrammatical sentences.
Furthermore, a comparison of Swahili with English samples showed that these
agrammatic symptoms were very similar in both languages. The final question
focused on whether the production of verb forms referring to a past time frame
was impaired in both languages. Time reference has been tested in several languages, but has not been examined in agrammatic spontaneous speech. This
question was precipitated by the need to establish whether the predictions of
the Past Discourse Linking Hypothesis (PADILIH) extend to both languages
of bilinguals, and more specifically to other agglutinative languages such as
Swahili. An analysis of the use of verb forms, taking into account both tense
and aspect, revealed a preference for verb forms referring to the present rather
than to the past by agrammatic (but not by non-brain-damaged) speakers in
both languages, suggesting the possibility of an underlying deficit for reference
to the past through verb inflection. The findings on the use of verb inflections
for time reference provided the basis for the subsequent study.
With respect to the second study, presented in Chapter 3, the Test for
Assessing Reference of Time (TART), designed to provide a comprehensive
assessment of production and comprehension of reference of time, was used to
address three research questions. The three questions were as follows: 1) Is
production of time reference to the past through verb inflection impaired in
both languages of a bilingual? 2) Is comprehension of time reference to the
past through verb inflection impaired in both languages of a bilingual? 3) Is
reference to the past similarly impaired in both Swahili and English for bilingual
speakers? By exploring these questions, we aimed to establish whether the
notable differences in the size of the verb inflection paradigm for time reference
in both languages can influence the performance of agrammatic speakers. The
relatively large number of affixes in the Swahili verb paradigm makes it more
complex, although the inflection for time reference is more regular compared
to that of English. As predicted, the findings concurred with the predictions
of the PADILIH. The agrammatic speakers were impaired in their production
and comprehension of time reference to past, but relatively spared in their time
reference to both the present and the future. Furthermore, a similar pattern of
impairment was manifested in both languages irrespective of the morphological
differences, as noted in the previous study. Our explanation of the problem
SUMMARY
141
with time reference to the past is based on Zagona’s (2003) assumption that
reference to the past is discourse linked, whereas both the present and future
are non-past (the future being a variant of the present), hence not discourse
linked. Discourse linked elements have to be processed by discourse syntax,
according to Avrutin (2000; 2006). This requires extra processing resources
which are not sufficiently available for agrammatic speakers due to their brain
damage.
For the third study, Chapter 4, we tested bilingual agrammatic speakers’
ability to comprehend sentences whose order of arguments is derived. Two
theories, the Trace Deletion Hypothesis (TDH) and the Derived Order Problem Hypothesis (DOP-H), formed the basis for this study, both predicting
difficulties with derived order sentences for agrammatic speakers. The TDH,
a representational account, predicts above chance level performance for sentences in which arguments are in base order (such as actives and subject relatives), and chance level performance when arguments are in a derived order
(i.e. non-canonical sentences such as passives and object relatives with and
without relative pronouns). The DOP-H, a processing account, also predicts
good performance for sentences whose arguments are in base order, and poor
performance for sentences with arguments in a derived order. However, since
the DOP-H is a processing account, interpretation of the results is not in terms
of a comparison to chance level
but rather in terms of (significantly) worse performance on sentences with
derived order of the arguments. Although these theories have been widely
tested among monolingual agrammatic speakers, no previous study has reported on bilinguals; hence the need to examine the patterns of comprehension
deficits that are likely to emerge in the structurally different languages of bilinguals. The results revealed that sentences in a derived order are more difficult to
comprehend than those in base order in both Swahili and English, corroborating the predictions of both theories to include bilingual agrammatic speakers.
Furthermore, there was a significant interaction effect between derived order
of arguments and embedding: sentences with an embedding (in this case, the
relative clauses) were more difficult to comprehend than simple declaratives.
The DOP-H can account for the further difficulty caused by embedding by
suggesting that embedding adds linguistic complexity to sentences, requiring
an extra operation to parse.
The final study, Chapter 5, examined the production of sentences in both
142
SUMMARY
base and derived word orders in Swahili and English. Sentences in which the
arguments are in base order (actives and subject clefts) and in derived orders
(passives and object clefts) were elicited, based on the predictions of DOP-H–
an overarching theory that makes similar predictions for both comprehension
and production. As predicted by the DOP-H, the results replicated the findings
from the previous study on comprehension: sentences in derived order (the
passives and object clefts) were more difficult to produce than those in base
order (the actives and subject clefts). Again, there was an interaction effect
with embedding, making the subject clefts more difficult than the simple actives
and the objects cleft more difficult than the passives.
In sum, these studies have shown that bilingual Swahili-English agrammatic
speakers are not clinically very different from monolingual agrammatic speakers in terms of how their language production and comprehension are affected
following brain damage. Their spontaneous speech in both languages is characterized by significantly (1) lower speech rate; (2) shorter utterances; (3) fewer
grammatical sentences; and (4) fewer embeddings. Furthermore, their production and comprehension of sentences is seriously affected by time reference
through verb inflection, word order and embedding. Sentence structures with
verb inflections for time reference to the past, those whose arguments are in
a derived (non-canonical) order, as well as those with embeddings, are poorly
comprehended and produced. The pattern of impairment is similar in both
languages (Swahili and English) irrespective of their differences in morphological structure, suggesting language representation in shared processing regions
of the bilingual brain.
Nederlandse Samenvatting
Dit proefschrift richtte zich op hoe agrammatisme zich in tweetalige sprekers
van Swahili en Engels manifesteert door stoornissen in werkwoordsinflectie en
in woordvolgorde te onderzoeken aan de hand van verschillende theorien over
agrammatisme. Of, en in welke mate, sommige van die taalkundige theorien
over agrammatisme betrekking hebben op tweetalige agrammatische sprekers
van Swahili en Engels komt uitgebreid aan bod in de vier hoofdstukken van dit
proefschrift.
De eerste studie, hoofdstuk 2, was gericht op het identificeren van de kenmerken van narratieve en spontane taal in agrammatisch Swahili, en het vergelijken van het gebruik van werkwoordsinflectie voor tempus en tijdsverwijzing (in
Swahili en Engels) door agrammatisch afatische individuen en individuen zonder hersenletsel door middel van drie hoofdonderzoeksvragen. De eerste vraag
erop gericht om te bepalen of er overeenkomsten of verschillen waren in taalproductie van het Engels van eentalige Amerikaanse, en tweetalige Keniaanse
afatische sprekers. Het doel van deze vraag was het vaststellen of spontanetaalanalyse van afatische sprekers van talen waarvoor geen gestandaardiseerde
tests beschikbaar zijn (bijvoorbeeld voor talen die in Kenia worden gesproken) genoeg is om agrammatisme te identificeren. De resultaten toonden een
opmerkelijke overeenkomsten aan tussen agrammatische fenomenen in beide
talen (Keniaans-Engels en Amerikaans-Engels) op typische agrammatische kenmerken: uitingslengte is korter, spreektempo is lager, en de proportie grammaticale zinnen en complexe zinnen is lager dan normaal. De tweede vraag diende
ertoe om vast te stellen wat de kenmerken van agrammatisme in Swahili zijn en
hoe vergelijkbaar ze zijn met de kenmerken van agrammatisme in Engels. Na te
hebben vastgesteld dat de afatische individuen agrammatisch waren in het En-
143
144
NEDERLANDSE SAMENVATTING
gels, werden aanvullende analyses uitgevoerd in Swahili en werden vergelijkingen gemaakt met de Engelse samples. Zoals verwacht vertoonden de agrammatische fragmenten van Swahili in vergelijking met de fragmenten van individuen
zonder hersenletsel kenmerken die over het algemeen agrammatisme karakteriseren: een verminderde taalproductie, een laag spreektempo, kortere uitingen,
beperkt gebruik van ingebedde zinnen, en naar verhouding veel agrammaticale
uitingen. Verder liet een vergelijking van fragmenten in Swahili en in Engels
zien dat deze agrammatische symptomen zeer vergelijkbaar waren in beide
talen. De laatste vraag focuste op of de productie van werkwoordsvormen die
naar het verleden verwijzen aangetast was in beide talen. Tijdsverwijzing is
in veel verschillende talen getest, maar is nog niet in agrammatische spontane
taal onderzocht. Deze onderzoeksvraag is voortgekomen uit de noodzaak om
vast te stellen of de voorspellingen van de Past Discourse Linking Hypothesis
(PADILIH) ook betrekking hebben op beide talen van tweetalige mensen, en
meer specifiek op andere agglutinerende talen zoals Swahili. Een analyse van
het gebruik van werkwoordsvormen die zowel met tempus als aspect rekening
houdt onthulde een voorkeur voor werkwoordsvormen die naar het heden verwijzen in plaats van naar het verleden voor agrammatische sprekers (maar niet
voor sprekers zonder hersenletsel) in beide talen. Dit suggereert de mogelijkheid van een onderliggende stoornis voor tijdsverwijzing naar het verleden
door middel van werkwoordsinflectie. De bevindingen op het gebied van werkwoordsinflectie voor tijdsverwijzing vormde de basis voor de volgende studie.
Met betrekking tot de tweede studie, te vinden in hoofdstuk 3, werd de Test
for Assessing Reference of Time: ‘Test voor het Onderzoeken van Tijdsverwijzing’ (TART) gebruikt, die ontworpen is om de productie en het begrip van
tijdsverwijzing te beoordelen om daarmee de onderzoeksvragen aan de orde te
stellen. De drie vragen waren als volgt: 1) Is productie van tijdsverwijzing naar
het verleden door werkwoordsinflectie aangetast in de beide talen van een tweetalige? 2) Is het begrip van tijdsverwijzing door werkwoordsinflectie aangetast
in de beide talen van een tweetalige? 3) Is verwijzing naar het verleden vergelijkbaar aangetast in zowel Swahili als Engels? Door deze vragen aan te kaarten
probeerden we vast te stellen of de opvallende verschillen in de grootte van het
werkwoordsinflectieparadigma voor tijdsverwijzing in beide talen de prestatie
van agrammatische sprekers kan benvloeden. Het relatief grote aantal affixen
van het werkwoordsinflectieparadigma van het Swahili maakt het een complexer paradigma, alhoewel de inflectie voor tijdsverwijzing regelmatiger is dan
NEDERLANDSE SAMENVATTING
145
die van het Engels. Zoals voorspeld stemden de bevindingen overeen met de
voorspellingen van de PADILIH. De productie en het begrip van tijdsverwijzing
naar het verleden van agrammatische sprekers was aangetast, maar de tijdsverwijzing naar het heden en de toekomst was relatief gespaard. Verder kwam het
aantastingspatroon op dezelfde manier naar boven in beide talen, onafhankelijk van de morfologische verschillen zoals in de voorgaande studie aangegeven.
Onze verklaring voor het probleem met tijdsverwijzing naar het verleden is
gebaseerd op Zagona’s (2003) aanname dat verwijzing naar het verleden een
koppeling in de discourse (vertoog) vereist, terwijl zowel heden als toekomst
niet-verleden zijn (met de toekomst als variant van het heden) en daarom niet
discourse-gekoppeld. Discourse-gekoppelde elementen moeten verwerkt worden door discourse-syntaxis volgens Avrutin (2000, 2006). Dit vereist extra
verwerkingscapaciteit, waarvan niet voldoende aanwezig is bij agrammatische
sprekers vanwege hun hersenletsel.
Voor de derde studie, hoofdstuk 4, hebben we het vermogen van tweetalige agrammatische sprekers getest om zinnen met een afgeleide argumentsvolgorde te begrijpen. Twee theorien, de Trace Deletion Hypothesis (TDH) en
de Derived Order Problem Hypothesis (DOP-H) vormden de basis van deze
studie. Beide voorspellen moeilijkheden met zinnen met afgeleide woordvolgorde voor agrammatische sprekers. De TDH, een representatieverklaring, voorspelt prestatie boven kansniveau voor zinnen waarin de argumenten in hun
basisvolgorde staan (zoals actieve zinnen en subjectsrelatieve bijzinnen), en
prestatie op kansniveau voor het omgekeerde (d.w.z. niet-canonieke zinnen
zoals passieve zinnen en objectsrelatieve bijzinnen met of zonder betrekkelijk
voornaamwoord). De DOP-H, een verwerkingsverklaring, voorspelt verder een
goede prestatie op zinnen waarvan de argumenten in de basisvolgorde staan,
en een slechte prestatie op zinnen waarvan de argumenten in afgeleide volgorde staan. Toch, omdat de DOP-H een verwerkingsverklaring is, verloopt
de interpretatie van de resultaten anders dan hierboven, beneden kansniveau,
namelijk eerder met betrekking tot (significant) slechtere prestatie op zinnen
met een afgeleide volgorde van de argumenten. Alhoewel deze theorien uitgebreid getest zijn met eentalige agrammatische sprekers, was er tot nu toe nog
geen studie gericht op tweetalige mensen. Derhalve bestaat de behoefte om
de patronen van de begripstoornis te onderzoeken die voorkomen in de structureel andere talen van tweetalige mensen. De resultaten tonen aan dat zinnen
met afgeleide volgorde van argumenten moeilijker te begrijpen zijn dan die met
146
NEDERLANDSE SAMENVATTING
basisvolgorde in zowel Swahili als Engels, wat bevestigt dat de voorspellingen
van beide theorien ook betrekking hebben op tweetalige mensen. Daarbij was
er een significante interactie tussen afgeleide argumentsvolgorde en inbeddingen: ingebedde bijzinnen (in dit geval betrekkelijke bijzinnen) waren moeilijker
te begrijpen dan hoofdzinnen (zonder inbedding). De DOP-H kan de hogere
moeilijkheidsgraad veroorzaakt door inbedding verklaren door te stellen dat
inbedding een extra lingustische complexiteit toevoegt aan zinnen die tot een
extra verwerkingsoperatie leidt.
De laatste studie, hoofdstuk 5, onderzocht de productie van zinnen in zowel
basisvolgorde als afgeleide volgorde in Swahili en Engels. Zinnen waarvan
de argumenten in basisvolgorde staan (actieve zinnen en subjectskloofzinnen)
en in afgeleide volgorde (passieve zinnen en objectkloofzinnen werden ontlokt
op basis van de voorspellingen van de DOP-H; een overkoepelende theorie
die zowel voor begrip als productie vergelijkbare voorspellingen doet. Zoals
door de DOP-H voorspeld werd, repliceerden de resultaten de bevindingen van
eerdere begripsstudies: zinnen met afgeleide volgorde (passieve zinnen en objectkloofzinnen) waren moeilijker te produceren dan zinnen met basisvolgorde
(actieve zinnen en subjectkloofzinnen). Wederom was er een interactie met
inbedding, waarbij de subjectkloofzinnen moeilijker bleken te zijn dan de enkel
actieve zinnen en de objectkloofzinnen moeilijker bleken dan de passieve zinnen.
Samenvattend hebben deze studies aangetoond dat tweetalige sprekers van
Swahili en Engels klinisch gezien niet sterk verschillen van eentalige sprekers
wat betreft hun stoornis op het gebied van taalproductie en -begrip ten gevolge
van hersenletsel. Hun spontane taal in beide talen wordt gekarakteriseerd door
(1) een lager spreektempo, (2) kortere uitingen, (3) minder grammaticaal correcte uitingen en (4) minder inbeddingen. Verder is hun productie en begrip
ernstig aangetast door tijdsverwijzing door middel van werkwoordsinflectie,
door woordvolgorde en door inbedding. Zinstructuren met werkwoordsinflectie voor tijdsverwijzing naar het verleden, met een afgeleide (niet-canonieke)
volgorde van de argumenten, en met inbeddingen worden slecht begrepen en geproduceerd. Het patroon van de stoornis is vergelijkbaar in beide talen (Swahili
en Engels) onafhankelijk van hun structurele (morfologische) verschillen, wat
taalrepresentatie in gedeelde verwerkingsgebieden in het tweetalige brein suggereert.
Appendices
147
148
APPENDICES
Appendix to Chapter 2
2.A
Swahili speech samples comprising the first 10
utterances of agrammatic participants in Chapter 2
EA
Mzee okoa msichana bahari...
Man save girl
sea
“The man save the girl”
mshipi vuta msichana...
belt
pull girl
“The belt pull the girl”
msichana oga bahari...
girl
bath sea
“The girl bath sea”
hewa...
“air”
mafuriko tele...
“flood
abundant”
mwokozi kuja haraka...
saviour come quickly
“Saviour come quickly”
a - ka
- okoa msichana...
he - CONSEC. - Save girl
“He save the girl”
mzee beba msichana inje
bahari...
man carry girl
outside sea
“The man carry the girl outside the sea”
Msichana...
Girl...
“The girl...”
mvulana panda kiti...
boy
climb seat
“The boy climb the seat”
6.3. FURTHER RESEARCH
149
SW
Kuna
msichana mmoja akona maji...
there is girl
one
has
water
“There is one girl who has water”
na ha-na
hiyo...
and NEG-with that
“and she does not have that...”
kuna
maji nyingi sana...
there is water a
lot
very
“There is a lot of water”
sasa kuna
mtu
mmoja a-na-taka
ku-m-saidia...
now there is person one
s/he-PRESENT-want INFIN-him/her-help
“Now, there is one person who wants to help her”
kwa sababu hiyo maji iko nyingi sana...
of
because that water is a lot
very
“Because that water is a lot”
Sasa a-na-jaribu
njia venye a-ta-fanya...
now s/he-PRESENT-try way how
s/he-FUTURE-do
“Now, he is trying to find a way out”
sababu iko
na
miti karibu moja...
because there is with trees nearby one...
“because there is a tree nearby”
na hiyo maji ni nyingi sana...
and that water is a lot
very
“And the water is a lot”
I-na-anza
kuwa nyingi sana...
It-PRESENT-start to be a lot
very
“The water level is rising”
sasa
now
huyo
that
“The
huyo mtu
a-na-taka
ku-m-saidia
that person s/he-PRESENT-want INFINITIVE-her/him-help
msichana...
girl
person wants to help the girl now”
150
APPENDICES
HJ
Mafuriko i-li-taka
ku-beba
huyu msichana...
floods
it-PAST-want INFINITIVE-carry this girl
“The floods wanted to carry this girl”
halafu huyu a-li-ona
yeye...
then
this s/he-PAST-see her/him
“This one saw her”
halafu a-ka-okoa
huyu...
then
s/he-CONSEC-save this
“He saved this one”
Na huyu a-li-po-piga
mayowe...
and this s/he-PAST-when-make noise
“and when this one made noise”
halafu huyu a-ka-m-sikia...
then
this s/he-CONSEC-her/him-hear
“Then this one heard her”
halafu a-ka-rudi
ku-m-toa...
then
s/he-CONSEC-return INFINITIVE-her/him-remove
“He came back to get her out”
halafu a-ka-m-lalisha
yeye
kwa sakafu...
then
s/he-CONSEC-her/him-lay her/him on floor
“Then he lay her on the floor”
halafu a-ka-finyilia
tumbo
yake...
then
s/he-CONSEC-press stomach hers
“Then he pressed her stomach”
halafu a-ka-tapika
maji...
then
s/he-CONSEC-vomit water
“Then she vomited water”
Huyu msichana a-li-po-kunywa
maji...
this
girl
s/he-PAST-when-drink water
“When this girl drank water”
6.3. FURTHER RESEARCH
151
MM
kuna
msichana kwa maji
There is girl
in
water
“There is a girl in the water”
na-fikiri
ni mafuriko
PRESENT-think is floods
“I think it is floods”
from water na kijana a-me-kuja
ku-m-uokoa
and boy
s/he-PRESENT-come INFINITIVE-her/him-save
msichana kwa maji...
girl
“The boy has come to save the girl from the water”
Watu wa ku-toka
kwa ....
people of INFINITIVE-come from
“People from....”
wa-na-enda
ku-okoa
watu
wa shida...
they-PRESENT-go INFINITIVE-save people of problems
“They are going to save people with problems”
kama hiyo mafuriko...
like
that flood
“Like the floods”
na sana sana kama sasa wako
na
mafuriko kwa mara
and very very like
now they are with floods
for times
mingi...
many
“and especially right now when they have lots of floods”
lakini mwisho a-me-pata
usaidizi...
but
last
s/he-PERFECT-get help
“But at last, she has got help”
msichana a-me-pata
watu
wa familia yake...
girl
s/he-PERFECT-get people of family hers
“The girl has found people from her family”
a-me-furahi...
s/he-PERFECT-happy
“She is happy”
152
APPENDICES
JK
Hapa u-na-weza
ku-ona
msichana...
Here you-PRESENT-can INFINITIVE-see girl
“Here you can see a girl”
ndiye
a-li-kuwa
a-na-zama
maji...
is the (one) s/he-PAST-be s/he-PRESENT-drown water
“She is the one who was drowning in the water”.
na iko
mtu
a-na-kuja
ku-m-uokoa...
and there is someone s/he-PRESENT-come INFINITIVE-her/him-save
“And there is someone coming to save her”
na ako na
shida
a-me-ji-shikilia
miti...
and has with problem s/he-PERFECT-it-hold trees
“And she has a problem she has held a stick”
na a-me-beba
kamba ya ku-okoa
msichana
and s/he-PERFECT-carry rope
for INFINITIVE-save girl
“And he has carried a rope to save the girl”
hii ni picha
ya msichana a-na-okole-wa...
this is picture of girl
s/he-PRESENT-save-PASSIVE
“This is a picture of a girl who is being saved”
a-na-okole-wa
kuto-ku-zama
kwa maji...
s/he-PRESENT-save-PASSIVE NEG-INFINITIVE-drown in
water
“She is being saved not to drown in water”
na jamaa wa...
yuko na
vitu...
and person from... has with things
“And the person from....has things”
a-na-jaribu
ku-m-toa
kutoka kwa hiyo
s/he-PRESENT-try INFINITIVE-her/her-remove out
of
that
maji...
water
“He is trying to get her out from the water”
na i-na-onekana
ana shida
ya ku-taka
and it-PRESENT-seem has problem of INFINITIVE-want
ku-zama...
INFIN-drown
“And it seems she has drowning problem”
6.3. FURTHER RESEARCH
153
LA
Kwenye hii picha
mtu
a-na-kuja
kwa maji...
in
this picture someone s/he-PRESENT-come into water
“In this picture, someone is coming into the water”
na kijiti a-na-m-patia
huyu...
and stick s/he-PRESENT-give this one
“And he is giving the stick to this one”
a-na-m-uliza
a-shikilie...
s/he-PRESENT-her/him-ask s/he-hold
“He is asking her to hold it”
huyu mwanamme a-na-m-patia
kijiti...
this man
s/he-PRESENT-her/him-give stick
“This man is giving her a stick”
a-weze
ku-m-vuta
ndani...
s/he-can INFINITIVE-her/her-pull inside
“For him to be able to pull her from the water”
lakini huyu mama a-na-taka
ku-shikilia...
but
this woman s/he-PRESENT-want to-hold
“But this woman wants to hold it”
lakini ha-wezi...
but
NEG-able
“But not able to...”
kwa
hivyo
a-na-onekana
ni kama a-ta-*drown...
because of that s/he-PRESENT-seem is like
s/he-FUTURE-drown
“It seems she will drown”
hii maji iko kali
sana...
this water is strong very
“This water is very strong”
woman kwa hivyo huyu mwanamme a-na-taka
and so
this man
s/he-PRESENT-want
ku-saidia
huyu mama
INFINITIVE-help this
“And so this man wants to help this woman”
154
2.B
APPENDICES
English Speech samples comprising the first 10
utterances of agrammatic participants in Chapter 2
EA
Floods rescue....
man rescue her from river or ocean
Girl...
rain...
me know it... girl...is...was swimming ...
after swimming around the lake...
after floods came with waves...
signal rescue...
the belt hold her back..
now swim out water.
HJ
What do we call the rescuers..
This was wanting to help this girl...
and then she went ...
and rescue the girl...
she wanted to rescue the girl...
the girl was help...
the rescuers...
they just went ...
and rescued this girl...
and she made it...
MM
This girl is drowning...
and I think a lot of rain...
and they are being swept by the water...
and this man is a...
maybe a....
what are these people...
maybe the Red Cross people...
and they would like to rescue the girl...
in the end the girl will be rescue...
Once upon a time this girl lived in the Rift-valley...
6.3. FURTHER RESEARCH
JK
I can see a girl here who is...
who looks like she is agonized ...
going through some kind of trouble...
I can see this guy is helping...
I don’t know...
basically she’s holding a piece of wood...
what is this?...
the belt...
he is a belt with him...
so far he is not caught the girl...
LA
The girl drowning...
the man trying to help her...
this man was walking along the river but he saw girl drowning ...
and decided to help her...
then he come in with stick give her but still they are not yet out...
I think the boy got hurt when he fall...
and the mother stopped the dishes to take the boy to hospital...
because this thing is very high...
the stool...
she didn’t because she was busy washing...
the mother was a bit...
155
156
APPENDICES
Appendix to Chapter 3
3.A
Accuracy in production and comprehension of
regular (n =13) and irregular (n =7) past tense in
English by agrammatic participants in Chapter 3
Production
Regular
Irregular
past-Tense past-Tense
(%)
(%)
SW
HJ
LA
MM
JK
EA
PN
JA
MW
VK
HS
JN
SS
mean %
3.B
9 (69.2)
2 (15.4)
11(84.6)
11(84.6)
13 (100.0)
3 (23.1)
1 (7.7)
10 (76.9)
5 (38.5)
6 (46.2
5 (38.5)
2 (15.4)
8 (61.5)
50.9
2
6
4
5
2
4
1
2
3
4
4
3
0 (0)
(28.6)
(85.7)
(57.1)
(71.4)
(28.6)
(57.1)
(14.3)
(28.6)
(42.9)
(57.1)
(57.1)
(42.9)
44.0
9 (45.0)
4 (20.0)
17 (85.0)
15 (75.0)
18 (90.0)
5 (25.0)
5 (25.0)
11(55.0)
7 (35.0)
9 (45.0)
9 (45.0)
6 (30.0)
11(55.0)
48.5
Comprehension
Regular
Irregular
past-Tense past-Tense
(%)
(%)
Compre.
past-Tense
(%)
13(100.0)
6 (46.2)
10 (76.9)
13(100.0)
13(100.0)
11(84.6)
6 (46.2)
12 (92.3)
9 (69.2)
7 (53.8)
9 (69.2)
8 (61.5)
11(84.6)
75.7
20(100.0)
7 (35.0)
17 (85.0)
20(100.0)
20(100.0)
18 (90.0)
9 (45.0)
16 (80.0)
15 (75.0)
11(55.0)
15 (75.0)
12 (60.0)
14 (70.0)
74.6
7 (100.0)
1(14.3)
7 (100.0)
7 (100.0)
7 (100.0)
7 (100.0)
3 (42.9)
4 (57.1)
6 (85.7)
4 (57.1)
6 (85.7)
4 (57.1)
3 (42.9)
72.5
The English verb pairs used in the Test for Assessing
Reference of Time (TART; Bastiaanse et al., 2008)
in Chapter 3
Examples
to read - to write the letter
Test items
to
to
to
to
to
to
to
Prod.
past-Tense
(%)
paint - to draw a square
tear - to glue the paper
pour - to drink the milk
eat - to peel the orange
push - to pull the trolley
sharpen - to break the pencil
knit - to sew the cloth
6.3. FURTHER RESEARCH
157
to empty - to fill the folder
to mop - to sweep the floor
to iron - to fold the sweater
3.C
The Swahili verb pairs used in the Test for Assessing
Reference of Time (TART; Abuom, et al., 2010) in
Chapter 3
Examples
Kusoma - kuandika barua
Test items
Kupaka - kuchora umbo
Kurarua - kubandika karatasi
Kumwaga - kunywa maziwa
Kula - kumenya chungwa
Kusukuma - kuvuta toroli
Kuchonga - kuvunja kalamu
Kufuma - kushona nguo
Kutoa - kuweka vitabu
Kupigadeki - kufagia sakafu
Kupigapasi - kukunja sweta
158
APPENDICES
References
Abuom, T. & Bastiaanse, R (2012). Characteristics of Swahili-English bilingual
agrammatic spontaneous speech and the consequences for understanding
agrammatic aphasia. Journal of Neurolinguistics, 25, 276-293.
Abuom, T. & Bastiaanse, R. (2013). Production and Comprehension of Reference of Time in Swahili-English bilingual agrammatic speakers. Aphasiology, 27, 157-177.
Abuom, T. & Bastiaanse, R. (in press). Sentence Production in Swahili-English
bilingual agrammatic speakers. Aphasiology.
Abuom, T., Sang, H., & Bastiaanse, R. (2010) Test for Assessing Reference of
Time (TART): Bilingual Swahili-English version. Groningen: University
of Groningen.
Abuom, T., Obler, L., & Bastiaanse, R. (2011). Using Swahili and English to
test explanations of agrammatism. Aphasiology, 25, 559- 575.
Abuom, T., Shah, E., & Bastiaanse, R. (2013). Sentence Comprehension in
Swahili-English agrammatic speakers. Journal of Clinical Linguistics &
Phonetics, 27, 355-370.
Abutalebi, J., Cappa, S. F., & Perani, D. (2005). What can functional imaging
tell us about the bilingual brain? Kroll, J. F. & De Groot, A. M. B.
(eds.) Handbook of bilingualism: Psycholinguistic approaches. (Ch. 25,
pp 497-515). New York: Oxford University Press.
Alajouanine, T. (1963). Dostoiewski’s epilepsy. Brain, 86, 209-218.
Albert, M. L., & Obler, L. K. (1978). The Bilingual Brain: Neuropsychological
and Neurolinguistic Aspects of Bilingualism. New York: Academic Press.
Alexiadou, A. & Stavrakaki S. (2006) Clause structure and verb movement in
a Greek-English bilingual patient with Broca’s aphasia: Evidence from
adverb placement. Brain and Language, 96, 207-220.
Anjarningsih, H. Y. (2012). Time reference in Standard Indonesian agrammatic
aphasia (Doctoral Dissertation, University of Groningen). Groningen Dissertations in Linguistics (GRODIL),101.
Anjarningsih & Bastiaanse. (2011). Verbs and time reference in Indonesian
agrammatic speech. Aphasiology, 25, 1562-1578.
159
160
REFERENCES
Anjarningsih, H.Y., Haryadi-Soebadi RD, Gofir A, Bastiaanse R. (2012) Characterising agrammatism in Standard Indonesian. Aphasiology, 26, 757-784.
Arabatzi, M. & Edwards, S. (2002). Tense and syntactic processes in agrammatic speech. Brain and Language, 80, 314-327.
Ashton, E.O. (1982). Swahili grammar. London: Longman, Green and Co.
Ltd.
Avrutin, S. (2000) Comprehension of discourse-linked and non-discourse-linked
questions by children and Broca’s aphasics. In Grodzinksy, Y., Shapiro, L.
& Swinney, D. (eds.) Language and brain: Representation and processing.
(pp 295-313). San Diego: Academic Press.
Avrutin, S. (2006). Weak syntax. In Amunts, K. & Grodzinsky, Y. (eds.)
Broca’s region. (pp 49-62). New York: Oxford Press.
Ballard, K. J. & Thompson, C. K. (1999). Treatment and generalization of
complex sentence production in agrammatism. Journal of Speech, Language, and Hearing Research, 42, 690-707.
Basso, A., Razzano, C., Faglioni, P., & Zanobio, M.E. (1990). Confrontation
naming, picture description and action naming in aphasic patients. Aphasiology, 4, 185-195.
Bastiaanse, R. (2008). Production of verbs in base position by Dutch agrammatic speakers: Inflection versus finiteness. Journal of Neurolinguistics,
21, 104-119.
Bastiaanse, R. (2013). Why reference to the past is difficult for agrammatic
speakers. Journal of Clinical Linguistics and Phonetics, 27, 244-263..
Bastiaanse, R., Bamyaci, E., Hsu, C., Lee, J., Yarbay Duman, T. & Thompson,
C.K. (2011). Time reference in agrammatic aphasia: A cross-linguistic
study. Journal of Neurolinguistics, 24, 652-673.
Bastiaanse, R., Bouma, G., & Post, W. (2009). Linguistic complexity and
frequency in agrammatic speech production. Brain and Language, 109,
18-28.
Bastiaanse, R. & Edwards, S. (2004). Word order and finiteness in Dutch and
English Broca’s and Wernicke’s aphasia. Brain and Language, 89, 91-107.
Bastiaanse, R., Edwards, S., Maas, E. & Rispens, J. (2003) Assessing comprehension and production of verbs and sentences: The Verb and Sentence
Test (VAST). Aphasiology, 17, 49-73.
Bastiaanse, R., Edwards, S., & Rispens, J. E. (2002b ). The Verb and Sentence
Test (VAST). Suffolk: Thames Valley Test Publishers.
Bastiaanse, R., Hugen, J., Kos, M., & van Zonneveld, R.(2002a ). Lexical,
morphological, and syntactic aspects of verb production in agrammatic
speakers. Brain and Language, 80, 142-159.
Bastiaanse, R. & Jonkers, R. (1998). Verb retrieval in action naming and
REFERENCES
161
spontaneous speech in agrammatic and anomic aphasia. Aphasiology, 12,
951-969.
Bastiaanse, R., Jonkers, R., & Thompson, C. K. (2008). Test for assessing
reference of time (TART). Groningen: University of Groningen.
Bastiaanse, R., Koekkoek, J., & Van Zonneveld, R. (2003). Object scrambling
in Dutch Broca’s aphasia. Brain and Language, 86, 287-299.
Bastiaanse, R., & Thompson, C.K. (2003). Verb and auxiliary movement in
agrammatic Broca’s aphasia. Brain and Language, 84, 286-305.
Bastiaanse, R. & Van Zonneveld, R. (2004). Broca’s aphasia, verbs and the
mental lexicon. Brain and Language, 90, 198-202.
Bastiaanse, R., & Van Zonneveld, R. (2006). Comprehension of passives in
Broca’s aphasia. Brain and Language, 96, 135-142.
Bastiaanse, R. & Van Zonneveld, R. (2005). Sentence production with verbs
of alternating transitivity in Broca’s agrammatic aphasia, Journal of Neurolinguistics, 18, 57-66.
Bates, E., Friederici, A., & Wulfeck, B. (1987). Grammatical morphology in
aphasia: evidence from three languages. Cortex, 23, 545-574.
Bates, E. A., Friederici, A. D., Wulfeck, B. B., & Juarez L. A. (1988). On the
preservation of word order in aphasia: Cross-linguistic evidence. Brain
and Language, 33, 323-364.
Bates, E., Wulfeck, B., & MacWhinney, B. (1991). Crosslinguistic research in
aphasia: An overview. Brain and Language, 41, 123-148.
Beeke S, Wilkinson R, Maxim J (2003). Exploring aphasic grammar 1: a single
case analysis of conversation. Clinical Linguistics and Phonetics, 17, 81 107.
Berndt, R.S. & Haendiges, A.N. (2000). Grammatical class in Word and Sentence production: Evidence from and Aphasic patient. Journal of Memory
and Language, 43, 249-273.
Berndt, R., Mitchun, C. & Haendiges, A. (1996). Comprehension of reversible
sentences in ‘agrammatism’: A meta-analysis. Cognition, 58, 289-308.
Berndt, R.S., Mitchum, C.S., Haendiges, A.N., & Sandson, J. (1997). Verb
retrieval inaphasia. Characterizing single word impairments. Brain and
Language, 56, 68-106.
Beretta, A. & Munn, A. (1998). Double-agents and trace-deletion in agrammatism. Brain and Language, 65, 404-421.
Bresnan, J. & Mchombo, S. (1987). Topic, Pronoun and Agreement in Chichewa.
Language, 63, 741-782.
Brookshire, R.H. & Nicholas, L.E. (1994). Speech sample size and test-retest
stability of connected speech measures for adults with aphasia. Journal of
Speech and Hearing Research, 37, 399-407.
162
REFERENCES
Burchert, F., Meiner, N. & De Bleser, R. (2008). Production of non-canonical
sentences in agrammatic aphasia: Limits in representation or rule application? Brain and Language, 104, 170-179.
Burchert, F., Swoboda-Moll, M., & De Bleser, R. (2005). Tense and agreement
dissociations in German agrammatic speakers: underspecification versus
hierarchy. Brain and Language, 94, 188-199.
Burgio, F. & Basso, A (1997). Memory and aphasia. Neuropsychologia, 35,
759-766.
Bybee, J. (2007). Frequency of use and the organization of language. Oxford
University Press.
Caramazza, A., & Berndt, R. S. (1985). A multicomponent deficit view of
agrammatic Broca’s aphasia. In M. L. Kean (Ed.), Agrammatism. London: Academic Press.
Caramazza, A. & Hillis, A. (1991). Lexical organization of nouns and verbs in
the brain. Nature, 349, 788-790.
Caramazza, A., & Zurif, E. B. (1976). Dissociation of algorithmic and heuristic
processes in language comprehension: Evidence from aphasia. Brain and
Language, 3, 572-582.
Centeno, J.G. & Anderson, R.T. (2011). A preliminary comparison of verb
tense production in Spanish speakers with expressive restrictions. Clinical
Linguistics & Phonetics, 25, 864-880.
Charlton, M.H. (1964). Aphasia in bilingual and polyglot patients: A neurological and psychological study. Journal of Speech and Hearing Disorders,
29, 307-311.
Chomsky, N. (1981). Lectures on government and binding. Dordrecht: Foris
Publications.
Chomsky, N. (1982). Some Concepts and Consequences of the Theory of Government and Binding. Cambridge. MA: The MIT Press.
Chomsky, N. (1995). The Minimalist Program. Cambridge, MA: MIT press.
Choy, J. J., & Thompson, C. K. (2010). Binding in agrammatic aphasia:
processing to comprehension. Aphasiology, 24, 551-579.
Clahsen, H. & Ali, M. (2009). Formal features in aphasia: Tense, agreement,
and mood in English agrammatism. Journal of Neurolinguistics 22, 436450.
Comrie, B. (1976). Aspect: An Introduction to the study of Verbal Apsect and
other related problems. Cambridge University Press.
Crepaldi, D, Ingignoli, C., Verga, R., Contardi, A., Semenza, C. & Luzzatti,
C. (2011). On nouns, verbs, lexemes, and lemmas: Evidence from the
spontaneous speech of seven aphasic patients. Aphasiology, 25, 71-92.
REFERENCES
163
De Diego-Balaguer, R., Costa, A., Sebastin-Galls, N., Juncadella, M., & Caramazza, A. (2004). Regular and irregular morphology and its relationship
with agrammatism: Evidence from two Spanish-Catalan bilinguals. Brain
and Language, 91, 212-222.
Dimmendaal, G. (2001). Language shift and morphological divergence in the
Nilotic area. Sprache und Geschichte in Afrika, 16/17, 83-124.
Dickey, M.W., Choy, J.J., & Thompson, C.K. (2007). Real-time comprehension
of whmovement in aphasia: Evidence from eyetracking while listening.
Brain and Language, 100, 1-22.
Dickey, M., Milman, L., & Thompson, C.K. (2005). Preception of functional
morphology in agrammatic Broca’s aphasia. Brain and Language, 95, 8283.
Dickey, M. W. & Thompson, C. K. (2007). The relation between syntactic and
morphological recovery in agrammatic aphasia: A case study. Aphasiology,
21, 604-616.
Drai, D., Grodzinsky, Y. 2006. The variability debate: More statistics, more
linguistics. Brain & Language, 76.2, 157-170
Dressler, W. 1985. Morphonology: the dynamics of derivation. Ann Arbor:
Karoma Press.
Edmonds, L., & Kiran, S. (2006). Effect of semantic naming treatment on
crosslinguistic generalization in bilingual aphasia. Journal of Speech Language and Hearing Research. 49, 729-748.
Fabbro, F. (2001). The bilingual brain: bilingual aphasia. Brain and Language,
79, 201-210.
Fabbro, F. (1999). The neurolinguistics of bilingualism. Hove, UK: Psychology
Press.
Fabbro, F. & Frau, G. (2001). Manifestations of aphasia in Friulian. Journal
of Neurolinguistics, 14, 255-279.
Faroqi-Shah, Y. & Dickey, M.W. (2009). On-line processing of tense and temporality in agrammatic aphasia. Brain and Language, 108, 97-111.
Faroqi-Shah, Y., & Thompson, C. K. (2007). Verb inflections in agrammatic
aphasia: Encoding of tense features. Journal of Memory and Language,
56, 129-151.
Faroqi-Shah, Y. & Waked, A. (2010). Grammatical category dissociation in
multilingual aphasia. Cognitive Neuropsychology, 27, 181-203
Frazier, L., & Friederici, A. (1991). On deriving the properties of agrammatic
comprehension. Brain and Language, 40, 51-66.
Friedmann, N. (2005). Degrees of severity and recovery in agrammatism:
climbing up the syntactic tree. Aphasiology, 19, 1037-1051.
Friedmann, N. (1998). Functional categories in agrammatic production: A
164
REFERENCES
crosslinguistic study. Unpublished doctoral dissertation. Tel Aviv University.
Friedmann, N. (2000). Moving verbs in agrammatic production. In R. Bastiaanse & Y. Grodzinsky (Eds.), Grammatical disorders in aphasia: A
neourolinguistic perspective (pp. 152-170). London: Whurr.
Friedmann, N. (2002). Question production in agrammatism: the Tree Pruning
Hypothesis. Brain and Language, 80, 160-187.
Friedmann, N. (2008). Traceless relatives: agrammatic comprehension of relative clauses with resumptive pronouns. Journal of Neurolinguistics, 21,
138-149.
Friedmann, N. & Grodzinsky, Y. (1997). Tense and agreement in agrammatic
production: Pruning the syntactic tree. Brain and Language, 56, 397-425.
Friedmann, N., & Gvion, A. (2003). Sentence comprehension and working
memory limitation in aphasia: A dissociation between semantic-syntactic
and phonological reactivation. Brain and Language, 86, 23-39.
Friedmann, N., Reznick, J., Dolinski-Nuger, D., & Soboleva, K. (2010). Comprehension and production of movement-derived sentences by Russian speakers with agrammatic aphasia. Journal of Neurolinguistics, 23, 44-65
Goodglass, H. (1968). Studies in the grammar of aphasics. In S. Rosenberg, &
J. Koplin (Eds.), Developments in applied psycholinguistic research. New
York: MacMillan.
Goodglass, H. & Kaplan, E. (1972). Boston Diagnostic Aphasia Examination.
Philadelphia: Lea & Febiger.
Goodglass, H., Kaplan, E. & Barresi, B. (2001) The Boston Diagnostic Aphasia
Examination. Philadelphia: Lippincott, Williams & Wilkins.
Goral, M. (2011). Treatment of grammatical disorders in bilingual aphasia.
Presentation at the Science of Aphasia XII, September 1-5, Barcelona
(Spain).
Goral, M., Levy, E.S., and Kastl, R. (2010). Cross-language treatment generalization: A case of trilingual aphasia. Aphasiology. 24, 170-187.
Grodzinsky, Y. (1984). The syntactic characterization of agrammatism. Cognition,16, 99-120.
Grodzinsky, Y. (1986). Language deficits and the theory of syntax. Brain and
Language, 27, 135-159.
Grodzinsky, Y. (1990). Theoretical Perspectives on Language Deficits. Cambridge, MA: The MIT Press.
Grodzinksy, Y. (1991). There is an entity called agrammatic aphasia. Brain
and Language, 41, 555-564.
Grodzinsky, Y. (1995). A restrictive theory of agrammatic comprehension.
Brain and Language, 51, 26-51.
REFERENCES
165
Grodzinksy, Y. (1999). The neurology of syntax: Language use without Broca’s
area. Behavioral and Brain Sciences, 23, 47-117.
Grodzinsky, Y. (2000). Overarching agrammatism. In Grodzinsky, Y., L.
Shapiro & D. Swinney, eds., 2000. Language and the brain. San Diego:
Academic Press.
Grodzinsky, Y., Piango, M. M., Zurif, E., & Drai, D. (1999). The critical role of
group studies in neuropsychology: Comprehension regularities in Broca’s
aphasia. Brain and Language, 67, 134-147.
Grosjean, F. (1994). Individual bilingualism. In R. E. Asher (ed.), The encyclopaedia of language and linguistics. (pp. 1656-1660). Oxford, UK:
Pergamon Press.
Gvion, A., & Friedmann, N (2012). Aphasia: Acquired language pathology. In
G. Khan (Ed.), Encyclopedia of Hebrew Language and Linguistics. Boston,
USA: Brill USA.
Haarmann, H.J. & Kolk, H.H. (1991). Syntactic priming in Broca’s aphasia:
Evidence for slow activation. Aphasiology, 5, 247-263.
Hagiwara, H. (1995). The breakdown of functional categories and the economy
of derivation. Brain and Language, 50, 92-116.
Hartmann, R.R.K. & Stork, F.C. (1972). Dictionary of language and linguistics. London: Applied Science Publishers.
Huber W, Poeck K, Weniger D. (2002). Aphasie. In: Hartje W, Poeck K, eds.
Klinische Neuropsychologie (pp.93-160). Stuttgart: Thieme.
Ivanova, M.V. & Hallowell, B. (2012). Validity of an eye-tracking methods to
index working memory in people with and without aphasia. Aphasiology,
26, 556-578.
Jacobs, B. J. & Thompson, C. K. (2000). Cross-modal generalization effects of
training noncanonical sentence comprehension and production in agrammatic aphasia. Journal of Speech, Language, and Hearing Research, 43,
5-20.
Jonkers, R., & Bastiaanse, R. (1998). How selective are selective word class
deficits? Two case studies of action and object naming. Aphasiology, 12,
245-256.
Jonkers, R. & Bruin, A. de (2009) Tense processing in Broca’s and Wernicke’s
aphasia. Aphasiology 23, 1252-1265.
Karanth, P., Ahuja, G. K., Nagaraj, D., Pandit, R., & Shivashankar, N. (1991).
Cross cultural studies of aphasia. In J. S. Chopra, K. Jagannathan, & I.
M. S. Sawhney (Eds.), Modern trends in neurology. New Delhi: Churchill
Livingstone.
Keach, C. (1995). Subject and Object markers as agreement and pronoun
incorporation in Swahili. In A. Akinlabi (Ed), Theoretical approaches to
166
REFERENCES
African Linguistics (pp.109-116). Trenton NJ: African World Press.
Kim, M., & Thompson, C. K. (2000). Patterns of comprehension and production of nouns and verbs in agrammatism: Implications for lexical organization. Brain and Language, 74, 1-25.
King, J. W., & Just, M. A. (1991). Individual differences in syntactic processing: The role of working memory. Journal of Memory and Language, 30,
580-602.
Knoph, M. (2011). Language assessment of a Farsi-Norwegian bilingual speaker
with aphasia. Clinical Linguistics & Phonetics, 25, 530- 539.
Kok, P., van Doorn, A. & Kolk, H. (2007). Inflection and computational load
in agrammatic speech. Brain and Language, 102, 273-283.
Kolk, H. H. J. (1998). Disorders of syntax in aphasia. Linguistic-descriptive
and processing approaches. In B. Stemmer & H. Whitaker (eds) Handbook
of Neurolinguistics (pp.249-260). San Diego, CA: Academic Press.
Krifka, M. (1995). Swahili. Syntax: Ein Internationales Handbuch Zeitgenossischer Forschung. In . J. Jacobs, A. von Stechow, W. Sternefeld and T.
Vennemann (Eds). An International Handbook of Contemporary Research
(pp1397-1418). Berlin: Walter de Gruyter.
Lee, J., Milman, L, & Thompson, C. K. (2008). Functional category production
in English agrammatism. Aphasiology, 22, 893-905.
Linebarger, M. C., Schwartz, M. F., & Saffran, E. M. (1983). Sensitivity to
grammatical structure in so-called agrammatic aphasics. Cognition, 13,
361-392.
Loogman, A. (1965). Swahili Grammar and Syntax, Duquesne studies-African
Series Editions. Pittsburg, P.A.: Duquesne Univesrsity Press.
Lorch, M.P. (1990). Cross-linguistic study of the agrammatic impairment in
verb inflection: Icelandic, Hindi, and Finnish cases’. In J.-L. Nespoulous
and P. Villiard, (eds.) Morphology, phonology and aphasia. Springer Verlag, New York.
Lukatela, K., Shankweiler D., & Crain, S. (1995). Syntactic processing in
agrammatic aphasia by speakers of a Slavic language. Brain and Language,
49, 50-76.
Marshall, J. C. (1986). The description and interpretation of aphasic language
disorder. Neuropsychologia, 24, 5-24.
Menn, L., & Obler, L. (Eds.). (1990). Agrammatic aphasia: A cross-language
narrative sourcebook. Philadelphia: John Benjamin.
Menn, L. & Obler, L. (1990). Cross-language data and theories of agrammatism. In Menn, L. & Obler, L.K. (eds.) Agrammatic aphasia: A crosslanguage narrative sourcebook, Vol. 2, 1369-1389. Amsterdam: John Benjamins.
REFERENCES
167
Miceli, G., Mazzucchi, A., Menn, L., & Goodglass, H. (1983). Contrasting cases
of Italian agrammatic aphasia without comprehension disorder. Brain and
Language, 19, 65-97.
Miceli, G., Silveri, C., Villa, G., & Caramazza, A. (1984). On the basis for the
agrammatic’s difficulty in producing main verbs. Cortex, 20, 207-220.
Miozzo, M., Costa, A., Hernndez, M., & Rapp, B. (2010). Lexical processing
in the bilingual brain: Evidence from grammatical/morphological deficits.
Aphasiology, 24, 262-287.
Miyake, A., Carpenter, P. A., & Just, M. A. (1994). A capacity approach
to syntactic comprehension disorders: Making normal adults perform like
aphasic patients. Cognitive Neuropsychology, 11, 671-717.
Mohammed, M.A. (2001). Modern Swahili grammar. Nairobi: East African
Educational Publishers LTD.
Myachina, E. N. (1981). The Swahili language: a descriptive grammar. London: Routlege & Kegan Paul.
Nanousi, V., Masterson, J., Druks, J., & Atkinson, M. (2006). Interpretable vs.
uninterpretable features: Evidence from six Greek-speaking agrammatic
patients. Journal of Neurolinguistics, 19, 209-238.
Nespoulous, J.-L., Dordain, M., Perron, C., Jarema, G., & Chazal, M. (1990).
Agrammatism in French: Two case studies. In L. Menn & L. Obler (Eds.),
Agrammatic aphasia: A cross-language narrative sourcebook. Philadelphia: John Benjamin.
Nespoulous, J.-L., Dordain, M., Perron, C., Ska, B., Bub, D., Caplan, D.,
Mehler, J., & Lecours, A. R. (1988). Agrammatism in sentence production
without comprehension deficits: Reduced availability of syntactic structures or of grammatical morphemes? A case study. Brain and Language,
33, 273-295.
Ngonyani, D. (1996). The Morphosyntax of Applicatives. Unpublished Doctoral dissertation, UCLA.
Obler, L. K., & Albert, M. L. (1996). Language and communication in aging
and dementia. In J. Birren (Ed.), Encyclopedia of gerontology (Vol. 2, pp.
1-6). San Diego, CA: Academic Press.
Obler, L. K., & Mahecha, N. (1991). First language loss in bilinguals with
brain-damage. In H. Seliger & R. Vago (Eds.), First language attrition:
Structural and theoretical perspectives (pp. 53-650). Cambridge, UK:
Cambridge University Press.
Olness, G.S. (2006). Genre, verb, and coherence in picture-elicited discourse of
adults with aphasia. Aphasiology, 20, 175-187.
Ouhalla, J. (1993). Functional categories, agrammatism and language acquisition. Linguistische Berichte, 143, 3-36.
168
REFERENCES
Ouhalla, J. (1990). Sentential negation, relativized minimality and the aspectual status of auxiliaries. The Linguistic Review, 7, 183-231.
Paradis, M. (1995). Introduction: The need for distinctions. In M. Paradis
(Ed.), Aspects of bilingual aphasia (1- 9). Oxford, UK: Pergamon Press.
Paradis, M. (2001). (ed.). Manifestations of aphasia symptoms in different
languages. Oxford: Pergamon Press.
Paradis, M. (1988) Recent Developments in studies of agrammatism: Their
import for the assessment of bilingual aphasia. Journal of Neurolinguistics,
3, 127-160.
Paradis, M., & Goldblum, M.C. (1989). Selected crossed aphasia in a trilingual
patient followed by reciprocal antagonism. Brain and Language, 36, 62-75.
Paradis, M. & Mwansasu, A. (1990) Bilingual Aphasia Test: English-Swahili
version. Hillsdale, NJ: LEA. 12pp.
Penke, M. (2001). Controversies about CP: a comparison of language acquisition and language impairment in Broca’s aphasia. Brain and Language,
77, 351-363.
Perrot, D. (1969). Teach yourself Swahili. New York: David Mckay Company,
Inc.
Piñango, M. (2000). Syntactic displacement in Broca’s agrammatic aphasia.
In: R. Bastiaanse & Y. Grodzinsky (Eds.), Grammatical disorders in aphasia (pp.75-87). London: Whurr Publishers.
Pollock, J. Y. (1989). Verb movement, universal grammar and the structure of
IP. Linguistic Inquiry, 20, 365-424.
Prins, R. & Bastiaanse, R. (2006). The early history of aphasiology: From the
Egyptian surgeons (c. 1700 bc) to Broca (1861). Aphasiology, 20, 762-791.
Rossi, E. (2007). Clitic production in Italian agrammatism. Groningen Dissertations in Linguistics (GRODIL). Groningen: University of Groningen.
Rossi, E. & Bastiaanse, R. & (2008). Spontaneous speech in Italian agrammatic
aphasia: A focus on verb production. Aphasiology, 22, 347-362.
Saffran, E. M., Berndt, R. S., Schwartz, M. F. (1989). The quantitative analysis
of agrammatic production: Procedure and data. Brain and Language, 37,
440-479.
Sanchez, M.E. (1996). Syntactic features in agrammatic production (Unpublished doctoral dissertation). University of British Colombia, Vancouver,
Canada.
Schwartz, M. F., Linebarger, M. C., Saffran, E. M., & Pate, D. S. (1987).
Syntactic transparency and sentence interpretation in aphasia. Language
and Cognitive Processes, 2, 85-113.
Semenza, C., Luzzatti, C., & Carabelli, S. (1997). Morphological representation of compound nouns: A study on Italian aphasic patients. Journal of
REFERENCES
169
Neurolinguistics, 10, 33-43.
Simonsen, H. G. & Lind, M. (2002). Past tense expression in a Norwegian man
with Broca’s aphasia. In Windsor, F., Kelly, M. L. & Hewkett, N. (eds.)
Investigations in clinical linguistics and phonetics (pp 44-56). London:
Lawrence Erlbaum.
Stavrakaki, S., & Kouvava, S. (2003). Functional categories in agrammatism:
Evidence from Greek. Brain and Language, 86, 129- 141.
Steere, E. (1976). Handbook of Swahili. London: Society for Promoting Christian Knowledge.
Stengel, E. & Zelmanowicz, J. (1933). Uber polyglotte motorische Aphasie.
Zeitschrift fur die gesamte Neurologie und Psychiatrie, 149, 292-311.
Thompson, C. K. (2003). Unaccusative verb production in agrammatic aphasia: the argument structure complexity hypothesis. Journal of Neurolinguistics, 16, 151-167.
Thompson, C. K., & Choy, J. (2009). Pronominal resolution and gap filling
in agrammatic aphasia: Evidence from eye movements. Journal of Psycholinguistic Research, 38, 255-283.
Thompson, C. K., Choy, J. J., Holland, A., & Cole, R. (2010). Sentactics
Computer-Automated Treatment of Underlying Forms. Aphasiology, 24,
1242-1266.
Thompson, C. K., Lange, K. L., Schneider, S. L., & Shapiro, L. P. (1997).
Agrammatic and non-brain damaged subjects’ verb and verb argument
structure production. Aphasiology, 11, 473-490.
Thompson, C. K., & Shapiro, L. P. (2005). Treating agrammatic aphasia within
a linguistic framework: Treatment of underlying forms. Aphasiology, 19,
1021-1036.
Thompson. C. K., Shapiro, L. P., Ballard, K. J., Jacobs, B. J., Schneider,
S. S., & Tait, M. E. (1997). Training and generalized production of Whand NP-movement structures in agrammatic aphasia. Journal of Speech,
Language, and Hearing Research, 40, 228-244.
Thompson, C. K., Shapiro, L. P., Kiran, S., & Sobecks, J. (2003). The role
of syntactic complexity in treatment of sentence deficits in agrammatic
aphasia: The complexity account of treatment efficacy (CATE). Journal
of Speech, Language, and Hearing Research, 46, 591-607.
Thompson, C. K., Shapiro, L. P., Li, L., & Schendel, L. (1995). Analysis
of verbs and verb argument structure: A method for quantification of
agrammatic language production. Clinical Aphasiology, 23, 121- 140.
Thompson, C. K., Shapiro, L. P., Tait, M. E., Jacobs, B. J., & Schneider,
S. L. (1996). Training Wh-question production in agrammatic aphasia:
Analysis of argument and adjunct movement. Brain and Language, 52,
170
REFERENCES
175-228.
Trousseau, A. (1864). ‘De l’aphasie, maladie d’crite recomment sous le nom
impropre d’aphmie,’ Gazette des Hpitaux Civils et Militaires 1: 13-14.
Tsapkini, K., Jarema, G., & Kehayia, E. (2001). Manifestations of morphological impairments in Greek aphasia: A case study. Journal of Neurolinguistics, 14, 281-296.
Varlokosta, S., Valeonti, N., Kakavoulia, M., Lazaridou, M., Economou, A., &
Protopapas, A. (2006). The breakdown of functional categories in Greek
aphasia: Evidence from agreement, tense, and aspect. Aphasiology, 20,
723-743.
Wenzlaff, M. & Clahsen, H. (2005). Finiteness and verb-second in German
agrammatism, Brain & Language, 92, 33-44.
Wenzlaff, M., & Clahsen, H. (2004). Tense and agreement in German agrammatism. Brain and Language, 89, 57-68.
Whitaker, H. A. (1998). Neurolinguistics from the Middle Ages to the premodern area: Historical vignettes. In B. Stemmer & H. A. Whitaker
(Eds.), Handbook of neurolinguistics (pp. 27-54). San Diego, CA: Academic Press.
Yarbay Duman, T., Aygen, G., & Bastiaanse, R. (2008). The production of
Turkish relative clauses in agrammatism: verb inflection and constituent
order. Brain and Language, 105, 149-160.
Yarbay Duman, T., Aygen, G., Özgirgin, N., & Bastiaanse, R. (2007). Object
scrambling and finiteness in Turkish agrammatic production. Journal of
Neurolinguistics, 20, 306-331.
Yarbay Duman, T. & Bastiaanse, R. (2009). Time reference through verb
inflection in Turkish agrammatic aphasia. Brain and Language, 108, 3039.
Yarbay Duman, T., Özgirgin, N., Altinok, N., & Bastiaanse, R. (2011). Sentence comprehension in Turkish Broca’s aphasia: An integration problem.
Aphasiology, 25, 908-926.
Zagona, K. (2003). Tense and anaphora: Is there a tense-specific theory of
coreference. In Barrs, A. (ed.) Anaphora: A Reference Guide. (pp 140171). Oxford: Blackwell Publishing.
Zagona, K. (in press). Tense, aspect and modality. In Dikken, M. den (ed.)
Encyclopedia of Generative Syntax. Cambridge: Cambridge University
Press.
Groningen Dissertations in Linguistics (Grodil)
1. Henriëtte de Swart (1991). Adverbs of Quantification: A Generalized Quantifier
Approach.
2. Eric Hoekstra (1991). Licensing Conditions on Phrase Structure.
3. Dicky Gilbers (1992). Phonological Networks. A Theory of Segment Representation.
4. Helen de Hoop (1992). Case Configuration and Noun Phrase Interpretation.
5. Gosse Bouma (1993). Nonmonotonicity and Categorial Unification Grammar.
6. Peter Blok (1993). The Interpretation of Focus: an epistemic approach to pragmatics.
7. Roelien Bastiaanse (1993). Studies in Aphasia.
8. Bert Bos (1993). Rapid User Interface Development with the Script Language Gist.
9. Wim Kosmeijer (1993). Barriers and Licensing.
10. Jan-Wouter Zwart (1993). Dutch Syntax: A Minimalist Approach.
11. Mark Kas (1993). Essays on Boolean Functions and Negative Polarity.
12. Ton van der Wouden (1994). Negative Contexts.
13. Joop Houtman (1994). Coordination and Constituency: A Study in Categorial
Grammar.
14. Petra Hendriks (1995). Comparatives and Categorial Grammar.
15. Maarten de Wind (1995). Inversion in French.
16. Jelly Julia de Jong (1996). The Case of Bound Pronouns in Peripheral Romance.
17. Sjoukje van der Wal (1996). Negative Polarity Items and Negation: Tandem
Acquisition.
18. Anastasia Giannakidou (1997). The Landscape of Polarity Items.
19. Karen Lattewitz (1997). Adjacency in Dutch and German.
20. Edith Kaan (1997). Processing Subject-Object Ambiguities in Dutch.
21. Henny Klein (1997). Adverbs of Degree in Dutch.
22. Leonie Bosveld-de Smet (1998). On Mass and Plural Quantification: The Case of
French ‘des’/‘du’-NPs.
23. Rita Landeweerd (1998). Discourse Semantics of Perspective and Temporal Structure.
24. Mettina Veenstra (1998). Formalizing the Minimalist Program.
25. Roel Jonkers (1998). Comprehension and Production of Verbs in Aphasic Speakers.
26. Erik F. Tjong Kim Sang (1998). Machine Learning of Phonotactics.
27. Paulien Rijkhoek (1998). On Degree Phrases and Result Clauses.
28. Jan de Jong (1999). Specific Language Impairment in Dutch: Inflectional Morphology
and Argument Structure.
171
172
GRODIL
29. Hae-Kyung Wee (1999). Definite Focus.
30. Eun-Hee Lee (2000). Dynamic and Stative Information in Temporal Reasoning:
Korean Tense and Aspect in Discourse.
31. Ivilin Stoianov (2001). Connectionist Lexical Processing.
32. Klarien van der Linde (2001). Sonority Substitutions.
33. Monique Lamers (2001).
Thematic Information.
Sentence Processing: Using Syntactic, Semantic, and
34. Shalom Zuckerman (2001). The Acquisition of “Optional” Movement.
35. Rob Koeling (2001). Dialogue-Based Disambiguation: Using Dialogue Status to
Improve Speech Understanding.
36. Esther Ruigendijk (2002). Case Assignment in Agrammatism: a Cross-linguistic
Study.
37. Tony Mullen (2002). An Investigation into Compositional Features and Feature
Merging for Maximum Entropy-Based Parse Selection.
38. Nanette Bienfait (2002). Grammatica-onderwijs aan allochtone jongeren.
39. Dirk-Bart den Ouden (2002). Phonology in Aphasia: Syllables and Segments in Levelspecific Deficits.
40. Rienk Withaar (2002).
Comprehension.
The Role of the Phonological Loop in Sentence
41. Kim Sauter (2002). Transfer and Access to Universal Grammar in Adult Second
Language Acquisition.
42. Laura Sabourin (2003). Grammatical Gender and Second Language Processing: An
ERP Study.
43. Hein van Schie (2003). Visual Semantics.
44. Lilia Schürcks-Grozeva (2003). Binding and Bulgarian.
45. Stasinos Konstantopoulos (2003). Using ILP to Learn Local Linguistic Structures.
46. Wilbert Heeringa (2004).
Levenshtein Distance.
Measuring Dialect Pronunciation Differences using
47. Wouter Jansen (2004). Laryngeal Contrast and Phonetic Voicing: A Laboratory
Phonology Approach to English, Hungarian and Dutch.
48. Judith Rispens (2004).
Dyslexia.
Syntactic and Phonological Processing in Developmental
49. Danielle Bougaı̈ré (2004). L’approche communicative des campagnes de sensibilisation
en santé publique au Burkina Faso: les cas de la planification familiale, du sida et de
l’excision.
50. Tanja Gaustad (2004). Linguistic Knowledge and Word Sense Disambiguation.
51. Susanne Schoof (2004). An HPSG Account of Nonfinite Verbal Complements in Latin.
52. M. Begoña Villada Moirón (2005). Data-driven identification of fixed expressions and
their modifiability.
53. Robbert Prins (2005). Finite-State Pre-Processing for Natural Language Analysis.
54. Leonoor van der Beek (2005). Topics in Corpus-Based Dutch Syntax.
55. Keiko Yoshioka (2005). Linguistic and gestural introduction and tracking of referents
in L1 and L2 discourse.
GRODIL
56. Sible Andringa (2005).
language proficiency.
173
Form-focused instruction and the development of second
57. Joanneke Prenger (2005). Taal telt! Een onderzoek naar de rol van taalvaardigheid
en tekstbegrip in het realistisch wiskundeonderwijs.
58. Neslihan Kansu-Yetkiner (2006). Blood, Shame and Fear: Self-Presentation Strategies
of Turkish Women’s Talk about their Health and Sexuality.
59. Mónika Z. Zempléni (2006). Functional imaging of the hemispheric contribution to
language processing.
60. Maartje Schreuder (2006). Prosodic Processes in Language and Music.
61. Hidetoshi Shiraishi (2006). Topics in Nivkh Phonology.
62. Tamás Biró (2006). Finding the Right Words: Implementing Optimality Theory with
Simulated Annealing.
63. Dieuwke de Goede (2006). Verbs in Spoken Sentence Processing: Unraveling the
Activation Pattern of the Matrix Verb.
64. Eleonora Rossi (2007). Clitic production in Italian agrammatism.
65. Holger Hopp (2007). Ultimate Attainment at the Interfaces in Second Language
Acquisition: Grammar and Processing.
66. Gerlof Bouma (2008). Starting a Sentence in Dutch: A corpus study of subject- and
object-fronting.
67. Julia Klitsch (2008). Open your eyes and listen carefully. Auditory and audiovisual
speech perception and the McGurk effect in Dutch speakers with and without aphasia.
68. Janneke ter Beek (2008). Restructuring and Infinitival Complements in Dutch.
69. Jori Mur (2008). Off-line Answer Extraction for Question Answering.
70. Lonneke van der Plas (2008). Automatic Lexico-Semantic Acquisition for Question
Answering.
71. Arjen Versloot (2008). Mechanisms of Language Change: Vowel reduction in 15th
century West Frisian.
72. Ismail Fahmi (2009). Automatic term and Relation Extraction for Medical Question
Answering System.
73. Tuba Yarbay Duman (2009).
Reference and Case.
Turkish Agrammatic Aphasia: Word Order, Time
74. Maria Trofimova (2009). Case Assignment by Prepositions in Russian Aphasia.
75. Rasmus Steinkrauss (2009). Frequency and Function in WH Question Acquisition. A
Usage-Based Case Study of German L1 Acquisition.
76. Marjolein Deunk (2009). Discourse Practices in Preschool.
Participation in Everyday Classroom Activities.
Young Children’s
77. Sake Jager (2009). Towards ICT-Integrated Language Learning: Developing an
Implementation Framework in terms of Pedagogy, Technology and Environment.
78. Francisco Dellatorre Borges (2010). Parse Selection with Support Vector Machines.
79. Geoffrey Andogah (2010). Geographically Constrained Information Retrieval.
80. Jacqueline van Kruiningen (2010).
Onderwijsontwerp
Probleemoplossing in interprofessioneel overleg.
als
conversatie.
81. Robert G. Shackleton (2010). Quantitative Assessment of English-American Speech
Relationships.
174
GRODIL
82. Tim Van de Cruys (2010). Mining for Meaning: The Extraction of Lexico-semantic
Knowledge from Text.
83. Therese Leinonen (2010). An Acoustic Analysis of Vowel Pronunciation in Swedish
Dialects.
84. Erik-Jan Smits (2010). Acquiring Quantification. How Children Use Semantics and
Pragmatics to Constrain Meaning.
85. Tal Caspi (2010). A Dynamic Perspective on Second Language Development.
86. Teodora Mehotcheva (2010). After the fiesta is over. Foreign language attrition of
Spanish in Dutch and German Erasmus Students.
87. Xiaoyan Xu (2010). English language attrition and retention in Chinese and Dutch
university students.
88. Jelena Prokić (2010). Families and Resemblances.
89. Radek Šimı́k (2011). Modal existential wh-constructions.
90. Katrien Colman (2011). Behavioral and neuroimaging studies on language processing
in Dutch speakers with Parkinson’s disease.
91. Siti Mina Tamah (2011). A Study on Student Interaction in the Implementation of
the Jigsaw Technique in Language Teaching.
92. Aletta Kwant (2011). Geraakt door prentenboeken. Effecten van het gebruik van
prentenboeken op de sociaal-emotionele ontwikkeling van kleuters.
93. Marlies Kluck (2011). Sentence amalgamation.
94. Anja Schüppert (2011). Origin of asymmetry: Mutual intelligibility of spoken Danish
and Swedish.
95. Peter Nabende (2011). Applying Dynamic Bayesian Networks in Transliteration
Detection and Generation.
96. Barbara Plank (2011). Domain Adaptation for Parsing.
97. Çağrı Çöltekin (2011). Catching Words in a Stream of Speech: Computational
simulations of segmenting transcribed child-directed speech.
98. Dörte Hessler (2011). Audiovisual Processing in Aphasic and Non-Brain-Damaged
Listeners: The Whole is More than the Sum of its Parts.
99. Herman Heringa (2012). Appositional constructions.
100. Diana Dimitrova (2012). Neural Correlates of Prosody and Information Structure.
101. Harwintha Anjarningsih (2012). Time Reference in Standard Indonesian Agrammatic
Aphasia.
102. Myrte Gosen (2012). Tracing learning in interaction. An analysis of shared reading
of picture books at kindergarten.
103. Martijn Wieling (2012). A Quantitative Approach to Social and Geographical Dialect
Variation.
104. Gisi Cannizzaro (2012). Early word order and animacy.
105. Kostadin Cholakov (2012). Lexical Acquisition for Computational Grammars. A
Unified Model.
106. Karin Beijering (2012). Expressions of epistemic modality in Mainland Scandinavian.
A study into the lexicalization-grammaticalization-pragmaticalization interface.
107. Veerle Baaijen (2012). The development of understanding through writing.
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175
108. Jacolien van Rij (2012). Pronoun processing: Computational, behavioral, and
psychophysiological studies in children and adults.
109. Ankelien Schippers (2012).
dependencies.
Variation and change in Germanic long-distance
110. Hanneke Loerts (2012). Uncommon gender: Eyes and brains, native and second
language learners, & grammatical gender.
111. Marjoleine Sloos (2013). Frequency and phonological grammar:
approach. Evidence from German, Indonesian, and Japanese.
An integrated
112. Aysa Arylova (2013). Possession in the Russian clause. Towards dynamicity in
syntax.
113. Daniël de Kok (2013). Reversible Stochastic Attribute-Value Grammars.
114. Gideon Kotzé (2013). Complementary approaches to tree alignment: Combining
statistical and rule-based methods.
115. Fridah Katushemererwe (2013). Computational Morphology and Bantu Language
Learning: an Implementation for Runyakitara.
116. Ryan C. Taylor (2013).
Pronoun Resolution.
Tracking Referents: Markedness, World Knowledge and
117. Hana Smiskova-Gustafsson (2013).
Perspective.
Chunks in L2 Development: A Usage-based
118. Milada Walková (2013). The aspectual function of particles in phrasal verbs.
119. Tom O. Abuom (2013). Verb and word order deficits in Swahili-English bilingual
agrammatic speakers.
Grodil
Secretary of the Department of General Linguistics
Postbus 716
9700 AS Groningen
The Netherlands