SOAS Working Papers in Linguistics and Phonetics
Volume 10, 2000 pp. 91-102
Constraints and processes: Evidence from Bemba, Herero and
Swahili*
Nancy Chongo Kula (University of Leiden) & Lutz Marten (SOAS)
1. Introduction
Licensing constraints play an important role in the characterisation of phonological
inventories within Government Phonology. They regulate the combinatory possibility
of phonological elements available in a given language and thus derive language
specific subsets out of all theoretically possible phonological expressions. While the
status of licensing constraints in this sense seems to be well understood, less attention
has been paid to the formal status of phonological processes. Yet it is the combination
of constraints on (static) element licensing and constraints on (dynamic) processes
which fully characterises phonological systems. In this paper we introduce the notion
of ‘process constraint’ as the dynamic counterpart of licensing constraint and
demonstrate the interaction of licensing constraints and process constraints by
discussing various possible analyses of two aspects of comparative Bantu – vowel
harmony and NC clusters – with reference to Bemba, Herero, and Swahili. The
comparison reveals that the interaction between these two theoretical tools requires a
further level of regulation, the exact characterisation of which is, however, left for
further research.
2. Vowel harmony in Swahili and Herero
As a first illustration of the role of licensing constraints (henceforth, LCs) and process
constraints (PCs) in GP, consider the case of ‘classic’ asymmetrical Bantu vowel
harmony of suffix vowels as found for example in Swahili1. Suffixes show three types
of behaviour; for some, including the applicative (Appl) suffix, there is an alternation
between /i/ following stem vowels /i, u, a/ (1a-c) and /e/ following /e, o/ (1d-e). A
second type of suffix such as the reversive suffix shows an alternation between /u/
before /i, u, a, e/ (2a-d), and /o/ following /o/ (2e), while suffixes with an /a/ vowel do
not show any alternation (3a-e):
(1a) pit-a
(1b) fung-a
(1c) kat-a
‘pass’
‘close’
‘cut’
pit-i-a
fung-i-a
kat-i-a
‘pass’ (Appl)
‘close’ (Appl)
‘cut’ (Appl)
(1d) let-a
(1e) tob-a
‘bring’
‘bore’
let-e-a
tob-e-a
‘bring’ (Appl)
‘bore’ (Appl)
*
All Bemba data are from the first named author; Herero data are from Jekura Kavari as part of the
SOAS Herero Project; Swahili data courtesy of Sauda Barwani. We are grateful to Jekura Kavari and
Sauda Barwani, as well as to Monik Charette for comments and Thilo Schadeberg for the map
software. This paper is truly work in progress and contains a number of shortcomings, the sole
responsibility for which lies of course with us.
1 Cf. Hyman (1999) for a discussion of Bantu vowel harmony patterns. The map at the end of this
article shows the distribution of the two types of harmony discussed here.
92
(2a)
(2b)
(2c)
(2d)
Nancy Chongo Kula & Lutz Marten
zib-a
fung-a
pak-a
teg-a
‘plug’
‘close’
‘load cargo’
‘set a trap’
zib-u-a
fung-u-a
pak-u-a
teg-u-a
‘unplug’
‘open’
‘unload cargo’
‘let go off (of a trap)’
(2e) song-a
‘press’
song-o-a
‘press together, wring’
(3a)
(3b)
(3c)
(3e)
(3f)
‘divide’
‘hide’
‘know’
‘love’
‘see’
gaw-an-a
fich-an-a
ju-an-a
pend-an-a
on-an-a
‘share’
‘hide each other’
‘know each other’
‘love each other’
‘see each other’
gaw-a
fich-a
ju-a
pend-a
on-a
An analysis of this harmony has to capture the asymmetry between front height
harmony, where the context is divided into (i, u, a) versus (e, o) and back height
harmony which partitions the context into (i, u, a, e) versus (o). This type of harmony
is typically, but not exclusively, found in Bantu languages with a five vowel system2.
A potential analysis of this situation is to assume the following LCs (4) which result
in the vocalic inventory in (5)3:
(4)
Licensing constraints for Swahili vowels
1. I must be head
2. U must be head
3. Phonological expressions must be headed
(5)
Swahili vocalic system
(I)
(I.A)
(A)
(U)
(U.A)
The LCs in (4) can be regarded as static constraints on the combination and role of the
phonological elements A, I, and U in Swahili, so that out of 19 theoretically possible
expressions resulting from the free combination of A, I, U without any restriction on
headedness, only 5 are allowed, representing the lexical vocalic system of Swahili.
As is standardly assumed in approaches employing monovalent features or
elements such as GP, the analysis of vowel harmony invokes the notion of element
spreading: one or several elements of the dominant nucleus are said to spread into
(and be subsequently shared by) the recessive nucleus. Spreading processes are
language specific and have to be explicitly stipulated so as to characterise which
element(s) spread out of, and into, which kind of expression(s) and roles. Although
these process constraints (PCs) as we will call them, appear to be of similar
2
Hyman (1999) lists 11 seven vowel system languages with this kind of harmony.
Cf. the analyses in Harris (1994), Cobb (1997), and Marten (1997) for several different proposals.
The general point we wish to make is unaffected by the details of the analysis of Swahili vowel
harmony.
3
Constraints and Processes
93
theoretical status as LCs, they have not been subject to as much discussion as LCs4.
For the case at hand, the PCs in (6) derive the schematic harmony patterns in (7) and
(8):
(6)
Process constraints for Swahili vowel harmony
1. A spreads as operator/non-head into I
2. A spreads into U in the presence of an U-bridge
(7)
Swahili front height harmony (e-i alternation)
Stem vowel
Suffix vowel
(I), (U), (A)
(I.A), (U.A)
(8)
(I)
(I.A)
A does not spread
Non-head A spreads into I
Swahili back height harmony (u-o alternation)
Stem vowel
Suffix vowel
(I), (U), (A), (I.A)
(U.A)
(U)
(U.A)
A does not spread
A spreads in the presence
of an U-bridge
The vowel harmony pattern of Swahili with its inherent asymmetry is thus explained
by two PCs, regulating the spreading of A into expressions containing I and into those
containing U. The absence of harmony with /a/ suffixes results simply from the
universal fact that a phonological expression cannot contain the same expression
twice, from which it follows that A cannot spread into A.
So far, then, we have introduced LCs and PCs which together correctly derive
the vocalic system of Swahili and the particular instance of vowel harmony found in
the language. The question we want to turn to now is the question of typological
variation.
The related Bantu language Herero has a five vowel system like Swahili and a
similar harmony pattern. In contrast to Swahili, however, height harmony in Herero
occurs not only in the context of the mid vowels /e/ and /o/, but also when following
stems with an /a/ vowel5:
(9a) pit-a ‘go out’
(9b) tuk-a ‘shake’
pit-ir-a
tuk-ir-a
‘go out’ (Appl)
‘shake’ (Appl)
4 Most commonly, the spreading elements in a given language are only informally given. Charette &
Göksel (1998) as well as Kaye (1999) argue that (some) properties of phonological processes can be
related to the LCs of a given language. This view is shared by Ritter (1999), who also provides a more
explicit statement of elemental processes in terms of parametric constraints. However, both these
analyses include additional assumptions about switching and self-licensing (C&G) or about the
‘strength’ of a particular element’ s licensing power (Ritter) which we wish to make more explicit with
our PCs.
5 As can be seen on the map, this type of harmony is mainly found in the South West of the Bantu
speaking area.
94
Nancy Chongo Kula & Lutz Marten
(9c) pat-a ‘close’
(9d) vet-a ‘hit by throwing’
(9e) ror-a ‘taste’
pat-er-a
vet-er-a
ror-er-a
‘close’ (Appl)
‘hit by throwing’ (Appl)
‘taste’ (Appl)
As can be seen from (9c), the suffix vowel is /e/ after an /a/ stem vowel. The harmony
with back vowel suffixes, and the absence of harmony with suffixes containing /a/ are
identical to Swahili. The question is then how to characterise the difference between
Swahili-type harmony and Herero-type harmony. Is the difference between the two
languages one of different vocalic inventories, and thus results from different LCs6, or
is it a difference of the harmony itself, and hence results from different PCs? As we
will show below, both alternatives can equally be formalised by using the notions of
LCs and PCs.
The first possible analysis of the difference between Swahili and Herero is to
assume that the languages have different LCs, and thus different vocalic systems:
(10) Licensing constraints for Herero vowels
1. I must be head
2. U must be head
3. A cannot be head
(11) Herero vocalic system
(I)
(I.A)
(A)
(U)
(U.A)
The difference between the LCs in (10) and the ones for Swahili (4, above) is the LC
3: whereas for Swahili, the third LC states that phonological expressions have to be
headed, the third LC for Herero states that A cannot be head, which implies that some
phonological expressions may be headless, in particular the expression containing A
only, as can be seen in (11). In contrast to the Swahili system, the /a/ of Herero is
headless. Now it is easy to see that these LCs, in combination with the PCs already
used for Swahili (6, above) derive the correct harmony pattern. Since the /a/ of Herero
is now represented as a non-head A, it falls under PC 1 according to which A spreads
as non-head into I:
(12) Herero height harmony (1)
Stem vowel
Suffix vowel
(I), (U)
(I)
(I.A), (U.A), (A)
(I.A)
A does not spread (it is not
present in the stem vowel)
A spreads as non-head
As can be seen in (12), the Herero harmony results from the same PCs, but differs
from the Swahili pattern since the LCs are different.
6
Cf. Ploch (1998) on this point.
Constraints and Processes
95
An alternative characterisation takes the LCs as given and attributes the crosslinguistic difference to different PCs:
(13) Process constraints for Herero vowel harmony
1. A spreads into I unconditionally
2. A spreads into U in the presence of an U-bridge
These processes result, in combination with the LCs (4, above), in the correct pattern
in (14):
(14) Herero height harmony (2)
Stem vowel
Suffix vowel
(I), (U)
(I)
(I.A), (U.A), (A)
(I.A)
A does not spread (it is not
present in the stem vowel)
A spreads into I unconditionally
In this alternative, the vocalic system of Swahili and Herero is taken to be identical,
but in Herero, in contrast to Swahili, A spreads into I from any position. The height
harmony involving back vowels, which is identical in the two languages, follows
from the requirement that there be an U-bridge, irrespective of the particular
combinations of LCs and PCs chosen for the representation of the front height
harmony.
What we have shown so far is that there are two theoretically interesting kinds
of statements which play a role in the analysis of phonological systems, LCs and PCs,
and that, furthermore, typological variation such as differences of Bantu vowel
harmony patterns, can be modelled by manipulating either LCs or PCs. The
formulation of these two kinds of constraints does not in itself lead to an answer to
the question which of the two possible analyses sketched in this section is to be
preferred. The idea is rather that independent parameters have to be invoked in order
to answer this question. On the assumption that elemental constituency can at least be
partly related to acoustic impressions (cf. Harris & Lindsey 1995), one might prefer to
assign the same sets of LCs to Swahili and Herero, and model the different harmonies
as differences of PCs. Similarly, identical LCs may be taken to reflect a closer
typological relation than identical PCs, and as generally being more important for the
typological characterisation of a given system. On the other hand, from an
information processing point of view (cf. Harris 2000), PCs are probably more
interesting since they can be used for marking domainhood in a way LCs cannot. The
respective role of LCs and PCs, and hence how they are invoked in characterising
phonological systems can thus only be answered with reference to further parameters.
In the case discussed in this section, that is, the two different kinds of Bantu vowel
harmony found in Swahili and Herero, the problem of formulating the right LCs and
PCs is facilitated by the relatively small number of elements involved in
characterising the relevant vowel systems. However, the task becomes harder, and the
scope for alternatives wider, when the representation of more complex consonantal
systems is considered. We turn to this in the next section.
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Nancy Chongo Kula & Lutz Marten
3. NC clusters in Bemba and Herero
Questions regarding the relation between LCs and PCs arise also with respect to
cross-linguistic (i.e. here cross-Bantu) variation of nasal-consonant (NC) clusters
between, for example Bemba and Herero. Is the underlying lexical representation of
consonants in the two languages identical, whilst the processes vary, or are the
processes the same but the underlying representations different; or, indeed, a
combination of both? Bemba, for example, permits voiceless consonants in NC
clusters, as in (15), whilst voiced stops are only found in NC clusters, when they are
derived from fricatives, liquids, or vowel-initial stems. In contrast, Herero permits
only voiced stops in NC clusters, so that stem-initial voiceless stops become voiced
(16a-c)7:
(15a) -pata ‘hate’
(15b) -tana ‘refuse’
(15c) -sala ‘choose’
mpata
ntana
nsala
‘I hate’
‘I refuse’
‘I refuse’
(Bemba)
(Bemba)
(Bemba)
(16a) -pe ‘new’
(16b) -twe ‘sharp’
(16c) -titi ‘small’
ombe
ondwe
onditi
‘new one’
‘sharp thing’
‘small thing’ 8
(Herero)
(Herero)
(Herero)
A number of studies in GP have provided evidence for the analysis of Bantu NC
clusters as onset-to-onset government domains (ONO), where government proceeds
from right to left, so that the stop governs the nasal (cf. e.g. Frost 1995, Kula &
Marten 1998, Kula 1999, Cooke 2000). It is also usually assumed that as part, or
reflex, of this government relation, certain elements in the participating phonological
expressions are shared. In particular the ‘place’ element is provided by the governing
stop and spreads into the underlyingly placeless nasal, resulting in the homorganicity
of nasal and stop9:
7
In addition, in Herero stem-initial s, h, m, n, lead to the loss of the nasal:
(i)
(ii)
(iii)
(iv)
o(N) + sengo
o(N) + honga
o(N) + menye
o(N) + nane
g
g
g
g
osengo
ohonga
omenye
onane
‘neck’
‘point’
‘springbuck’
‘needle’
*onsengo
*onhonga
*ommenye
*onnane
We leave the analysis of this process for future research.
Forms are in Herero spelling; <t> is a voiceless interdental plosive, <d> its voiced counterpart.
9 Following our analysis in Kula & Marten (1998) we represent stops without glottal elements, but this
is independent of the general point we are making here.
8
Constraints and Processes
(17a) mpata ‘I hate’
97
(17b) ntana ‘I refuse’
O
N
O
O
N
O
X
X
X
X
X
X
U
L
U
H
A
L
A
H
[m]
[p]
[n]
[t]
The underlying representation of the nasal part of the NC clusters in (17) can be given
as simply (L) provided that the following stop has a place element (one of U, A, and I)
and that there is a PC to the effect that this element spreads leftward into expressions
containing (solely) L. The absence of a place element results in a ‘default’ velar
nasal10. A palatal nasal occasionally results from cases of I spreading from a
following nucleus which need not concern us here, as we will not focus on the exact
details of homorganicity here (but cf. Kula & Marten 1998), but rather turn to the
difference in obligatory voicing between Bemba and Herero. We are going to show
that this difference can be, like the vowel harmony cases, analysed as a difference of
LCs or as a difference of PCs.
First, we assume that headed L is the representation of nasality, while nonheaded L is the representation of voicing11. Given this, we can then analyse voicing as
rightward L spreading from the head position of the nasal to the operator position of
the stop:
(18) O
N
O
X
X
X
Place
L
Place
L
Place element spreads: homorganicity
L spreading: voicing
Although there is no mandatory voicing in Bemba NC clusters, there is evidence for
L-spreading in the language, namely strengthening of stems beginning with /l/ and /ß/
(19) and nasal harmony (20b):
(19a) -lek-a
(19b) -ßil-a
‘stop’
‘sew’
ndeka‘I stop’
mbila
‘I sew’
(20a) -fik-a
(20b) -tan-a
‘arrive’
‘refuse’
fik-il-a
tan-in-a
10
‘arrive for’
‘refuse for’
See e.g. Piggott (2000) for a discussion of velar nasals as default interpretations.
Cf. i.a. Ploch (1998), Nasukawa (1997). The analysis of Bemba NC clusters here follows Kula &
Marten (1998).
11
98
Nancy Chongo Kula & Lutz Marten
The stems in (19) have an initial liquid or fricative which becomes a voiced stop (/d/
and /b/ respectively) when preceded by a nasal prefix such as the 1st person present
tense personal prefix. We are following Kula & Marten (1998) in assuming that the
strengthening cases result from an L element spreading from the nasal into the steminitial position under the condition that the target expression contains exclusively a
single non-headed expression, namely (U) as a representation of /ß/ and (A) as a
representation of /l/. Due to well-formedness conditions on governors, the governor
has to be headed, and since identical expressions may not be adjacent at the melodic
tier (since this would result in an OCP violation), the place element, rather than L,
becomes head, which accounts for the stop quality of the expression:
(21) O
N
X
X
O
+
L
nasal
prefix
g
X
O
N
O
X
X
X
U
U
L
U
L
[ß]
[m]
[b]
The analysis of strengthening as L spreading can be extended to nasal harmony, where
suffixes containing /l/ such as the applicative have a harmonised variant where the /l/
is changed into /n/ if the stem-final consonant is a nasal (20b). Nasal harmony can be
analysed as L spreading on the onset-projection across filled nuclei, where, however,
L may, and indeed does, become head since the two expressions are now separated by
the intervening nucleus, and no OCP context obtains:
(22) tan-a ‘refuse’ + -il-
g
tan-in-a
O
N
O
N
O
N
X
X
X
X
X
X
[t]
[a]
A
L
[i]
A
L
‘refuse for’
[a]
As can be seen in (22), the underlying representation of /l/ is (A), as already
mentioned above in the discussion of -leka, and the L of the nasal spreads into the
expression to result in (A.L) (see Kula & Marten 1998 for details). There is thus
evidence for L spreading in Bemba. The same processes are found in Herero:
Constraints and Processes
99
(23a) -vang-a
(23b) -rond-a
(23c) -zep-a
‘like, want’
‘climb’
‘kill’
ombang-o
ondonond-e
ondep-ero
‘will’
‘climb’ (N)
‘killing’ (N)12
(24a) -tin-a
(24b) -tum-a
(24c) -ram-a
(24d) -pem-a
(24e) -ton-a
‘whine’
‘send’
‘choke’
‘blow one’ s nose’
‘hit’
mba tin-in-e
mba tum-in-e
mba-ram-en-e
mba-pem-en-e
mba-ton-en-e
‘I have whined’
‘I have sent’
‘I have choked’
‘I have blown my nose’
‘I have hit’
Both Bemba and Herero have L spreading into simplex expressions if we assume that
in both languages the strengthened initial consonants can be analysed as simplex
expressions, e.g. Bemba /l/ and Herero /r/ as (A), Bemba /ß/ and Herero /v/ as (U) and
Herero /z/ as (I). We thus have a situation similar to the vowel harmony cases
discussed above. Both Herero and Bemba have NC clusters and similar associated
behaviour, while they differ with respect to post-nasal voicing, which is absent in
Bemba, but obligatory in Herero. This situation, despite being more complex than the
vowel harmony, can equally be analysed by invoking differences in LCs and PCs. We
concentrate here on the relevant subset of expressions, rather than defining the whole
inventory for the languages, and thus have the following LCs for Bemba:
(25) LCs for Bemba consonants
1. A, U do not combine
2. H, L must be head
3. A, U cannot be head
These LCs derive the subset of the Bemba consonants relevant to the discussion.
Recall that voiced stops are only derived in NC clusters and are thus excluded from
the lexical representation in (26)13:
(26) Elements for Bemba consonants (subset)
p
(U.H)
t
(A.H)
k
(H)
m
(U.L)
n
(A.L)
N
(L)
ß
(U)
l
(A)
Given this inventory, homorganicity, strengthening and nasal harmony as discussed
above can be captured by postulating the following PCs:
12
Herero orthographic <z> is a voiced interdental fricative [D].
This is one of the main motivations why we do not constrain the output of phonological processes by
lexical LCs.
13
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Nancy Chongo Kula & Lutz Marten
(27) PCs for Bemba NCs
1. L spreads rightwards into headless expressions
2. U, A spread leftwards into simplex L expressions
The combination of LCs and PCs supports the analysis of Bemba NCs outlined above.
The interesting question is now how Herero NCs relate to this system. Again, we
consider two possibilities. First, we adjust the LCs so that the PCs in (27) result in the
voicing facts. To achieve this, we have to make the targeted voiceless stops headless:
(28) LCs for Herero consonants
1. H, L, I do not combine
2. A, U, I do not combine
3. L must be head
4. Only L can be head (= H, A, U, I cannot be head)
The difference to the Bemba system is, in addition to the new element I, that LC 3 in
(28) includes only L as being obligatorily head, while in LC 4, H (and I) have been
added to the expressions which cannot be heads. The LCs result in the following
partial inventory:
(29) Elements for Herero consonants (subset) (1)
p
(U.H)
t
(A.H)
m
(U.L)
n
(A.L)
v
(U)
r
(A)
t
(I.H)
k
(H)
N
(L)
z
(I)
The voiceless stops are now represented as headless expressions. Consequently,
according to the PCs, L spreads into these expressions, where presumably the H
element is suppressed, so that headed voiced stops with L operator result14. Thus the
different facts can be derived by postulating two different sets of LCs while
maintaining identical PCs for Bemba and Herero.
The alternative is to use the LCs developed for Bemba (modulo the I element)
for Herero and change the PCs. Given the LCs and inventory in (25, 26, above), the
following PCs derive the Herero voicing:
(30) PCs for Herero NCs
1. L spreads rightwards
2. U, A spread leftwards into simplex L expressions
14 There are problems with the homorganicity in NCs with t and z, i.e. those expressions containing I,
since the nasal in these cases is alveolar, not palatal. We leave this for future research.
Constraints and Processes
101
The new PC 1 states that L spreads unconditionally rightwards. This works, given the
inventory, since all expressions which undergo either voicing or strengthening are
characterised by the absence of L. L does not spread into nasals since nasals already
contain L.
A more radical alternative, which assumes the PCs in (30), represents the
voiceless stops as headed simplex expressions:
(31) Elements for Herero consonants (subset) (2)
p
(U)
t
(A)
m
(U.L)
n
(A.L)
v
(U)
r
(A)
t
(I)
k
(H)
N
(L)
z
(I)
This system codes the difference between the fricatives, which become strengthened,
and the stops, which become voiced, solely by means of headedness. The only
complex expressions in the inventory are thus those containing L. The system can be
generated from the following LCs:
(32) LCs for Herero consonants (2)
1. L, H must be head
2. A, U, I, H do not combine
3. Only L licenses operators
Again, L can be characterised as spreading unconditionally, or more restrictedly as
spreading into simplex expressions, since the expressions not affected by a nasal
prefix are those already containing L.
4. Conclusion
In this paper, we have discussed the notion of Process Constraint and the interaction
of PCs and LCs with respect to two examples from comparative Bantu: Vowel
harmony and NC clusters. We have used exclusively (selected) phonological
behaviour to establish LCs and PCs, which we take as basic for phonological analysis,
and we have seen that there may be several ways to analyse the same phonological
system. In order to discriminate between competing analyses, higher-order parameters
may be invoked, such as the phonetic/acoustic representation of elements, or ease of
learnability/acquisition. Another obvious direction of enquiry is to formulate
constraints on the well-formedness of possible LCs and PCs, in the spirit of the
proposals in Ploch (1998) or Ritter (1999). However, we hope to have shown that the
explicit distinction between LCs and PCs helps to provide a format for this
discussion.
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Nancy Chongo Kula & Lutz Marten
References
Charette, Monik & Asli Göksel, 1998, ‘Licensing constraints and vowel harmony in
Turkic languages’ , in Eugeniusz Cyran, ed., Structure and Interpretation:
Studies in Phonology, Lublin: Pase, 65-89.
Cobb, Margaret, 1997, Conditions on Nuclear Government in Phonology, doctoral
dissertation, SOAS, University of London.
Cooke, Sheryl, 2000, A Government Phonology Perspective on Palatalization in
Zulu, MA thesis, SOAS, University of London.
Frost, Marie, 1995, A Government Phonology Perspective on Sound Change in
Luganda, MA thesis, SOAS, University of London.
Harris, John, 1994, ‘Monovalency and opacity: Chichewa height harmony’ , UCL
Working Papers in Linguistics 6, 509-547.
Harris, John, 2000, ‘Phonology as information interface’ , paper delivered at
University College London.
Harris, John & Geoff Lindsey, 1995, ‘The elements of phonological representation’ ,
in Jacques Durand & Francis Katamba, eds., Frontiers of Phonology, Harlow:
Longman, 34-79.
Hyman, Larry M., 1999, ‘The historical interpretation of vowel harmony in Bantu’ , in
Jean-Marie Hombert & Larry M. Hyman, eds., Bantu Historical Linguistics:
Theoretical and Empirical Perspectives, Stanford, Cal.: CSLI, 235-295.
Kaye, Jonathan, 1999, ‘Working with licensing constraints’ , ms. Guandong
University of Foreign Studies.
Kula, Nancy Chongo, 1999, ‘On the representation of NC clusters in Bemba’ , in
Renée van Bezooijen & René Kager, eds., Linguistics in the Netherlands 1999,
Amsterdam: Benjamins, 135-148.
Kula, Nancy Chongo & Lutz Marten, 1998, ‘Aspects of nasality in Bemba’ , SOAS
Working Papers in Linguistics & Phonetics 8, 191-208.
Lowe, John B. & Thilo C. Schadeberg, 1997, Bantu MapMaker, v. 3.1 (computer
program), Berkley & Leiden.
Marten, Lutz, 1997, ‘Licensing constraints for Swahili vowel harmony’ , in Stephen
Markve, Evelien Pennings & Ayumi Tsukiashi, eds., PLUM 2: Proceedings
from the Sixth Manchester Postgraduate Linguistics Conference, 239-255.
Nasukawa, Kuniya, 1997, ‘Melodic structure in a nasal-voice paradox’ , UCL Working
Papers in Linguistics 9, 403-423.
Piggott, Glyne, 2000, ‘Deconstructing coda licensing’ , paper delivered at SOAS,
University of London.
Ploch, Stefan, 1998, ‘Non-switch harmony in Yawelmani (and Turkish and Yakha)’ ,
SOAS Working Papers in Linguistics and Phonetics 8, 209-238.
Ritter, Nancy A., 1997, ‘Headedness as a means of encoding stricture’ , HIL
Phonology Papers III, 333-365.
Ritter, Nancy A., 1999, ‘The effect of intrasegmental licensing conditions on element
spreading’ , in S. J. Hannahs & Mike Davenport, eds., Issues in Phonological
Structure, Amsterdam: Benjamins, 53-72.