Nonword Repetition and Word/Nonword Discrimination: Comparing Dyslexia and
Language-Learning Disability
Christine Gray & Stacy Wagovich, The University of Missouri
BACKGROUND
Children with SLI and with dyslexia have
distinguishing features but often the two
disorders co-occur (Catts, Adlof, Hogan &
Weismer, 2005).

Children struggle with reading for different
reasons. Children who exhibit poor reading
comprehension also tend to exhibit poor
language comprehension with normal
phonological processing, while children with poor
decoding skills alone show the opposite profile
(Cain, Oakhill & Bryant, 2000; Catts, Adlof &
Weismer, 2006).

who obtained scores above the 25th percentile on
the Letter-Word Identification and the Word Attack subtests of
the Woodcock-Johnson, but below a standard score of 85 on
either the CELF receptive or CELF expressive composite score
were included in the “SLI” group.
 Those

Based on prior research (e.g., Catts et al.,
2005) we predicted that the DYS/COMBO
group would perform more poorly on nonword
repetition than the SLI group.
Additionally, we expected that the DYS/
COMBO group would have greater difficulty
on the checklist word/nonword discrimination
task because of its emphasis on decoding.

were audio recorded and later analyzed by syllable.
For those syllables with no errors, participants received one
point. For those syllables with one or more errors, no credit was
given.
 Inter-rater
Independent sample t-tests were used to compare the performance of the
SLI group with the performance of the DYS/COMBO group on the
checklist and NWR tasks.
 No statistically significant differences were found between the groups
for identifying common words or nonwords on the checklist.
100
Participants
 Twenty participants, ages 12;8 to 18;10, were
selected from a previously obtained sample of
30 children who had been referred by teachers
or parents because of reported difficulties in
reading and/or language in school.
of the participants passed a hearing
screening of 1000, 2000 and 4000 Hz at 20 dB
HL. In addition, each scored within or above
1.0 SD of the mean on a nonverbal reasoning
task (Symbolic Relations subtest of the Detroit
Test of Learning Aptitude-4, Hammill, 1998),
with one exception.*
t = 1.98
p = .071
75
t = 1.87
p = .086
t = 1.74
p = .105
50
2 Syllables
one participant in the SLI group, one NWR 4 syllable item
was not recorded due to examiner error. Percentages of
accuracy were computed accordingly.
completed a checklist designed by the second
author which contained common words, rare words, and
nonwords (in one of three randomized sets). First, participants
wrote definitions or sentences for words they knew. Next, they
reviewed the list again, circling any words they knew were real,
but could not define or use in a sentence. This procedure is an
adaptation based on Durso and Shore (1991; Shore & Durso,
1990; Schwanenflugel, Stahl, & McFalls, 1997).
 These
data were analyzed by merging all circled words and
words for which the participant attempted a definition or
sentence, since both reflected the participant’s impression that
the words were real lexical entries within the English language.
 A “checklist
percentage difference” score was found by
subtracting the percentage of nonwords mistakenly identified
as real words from the percentage of real words correctly
identified as real words on this task.
Ceiling effects were observed to impact NWR 2 syllable scores
for many children.

It appears that the small sample size of the study resulted in
low statistical power. Effect size analysis suggested that, had
the samples been larger, significant group differences on the
NWR task would have emerged.

Since the sample was collected retrospectively, more lenient
criteria for the groupings (25th percentile and below on
subtests of decoding versus above the 25th percentile on
subtests of decoding) were used in order to establish
comparison groups and retain the largest sample size
possible. The 25th percentile criterion has been used
previously in the literature (Catts et al., 2006).

The finding of trends toward group differences with large effect
sizes for NWR total, 6 syllable and 4 syllable scores is
important because these trends exist despite the fact that the
DYS/COMBO group’s mean CELF expressive score (89.0) did
not differ significantly from that of the SLI group’s mean CELF
expressive score (90.54). It appears that the trends seen
resulted from differences other than global expressive
language abilities.

Cain, K., Oakhill, J., & Bryant, P. (2000). Phonological skills
and comprehension failure: A test of the phonological
processing deficit hypothesis. Reading and Writing: An
Interdisciplinary Journal, 13, 31-56.

Catts, H.W., Adlof, S. M., Hogan, T. P., & Ellis, Weismer, S.
(2005). Are specific language impairment and dyslexia
distinct disorders? Journal of Speech, Language, and
Hearing Research, 48, 1378-1396.

Catts, H.W., Adlof, S. M. & Weismer, S. E. (2006).
Language deficits in poor comprehenders: A case for the
simple view of reading. Journal of Speech, Language and
Hearing Research, 49, 278-293.

Nation, K. & Snowling, M.J. (1998). Individual differences
in contextual facilitation: Evidence from dyslexia and poor
reading comprehension. Child Development, 69,
996-1011.
0
4 Syllables
6 Syllables
Total NWR Score
Nonword Repetition Task
 Participants

SELECTED REFERENCES
25
reliability for this task was 90.6%.
 Each
* One participant scored -1.3 SD on Symbolic
Relations
SLI
DYS/COMBO
t = 1.48
p = .157
Figure 1. Mean Nonword Repetition Accuracy by Group
Nonword Repetition Total Score in Percent

The finding that the Letter-Word Identification subtest of the
Woodcock-Johnson is correlated with the NWR task supports
previous findings in the literature that children who have
difficulty with decoding also perform less well on NWR tasks
(Nation & Snowling, 1998).
differences were not significant, effect sizes were large for
NWR total score (d=.85), NWR 4 syllable (d=.89), and NWR 6 syllable
(d=.78).
 For
METHOD

 Although
the SLI group, n=10, and for the DYS/COMBO group,
n=13. However, data on NWR were missing for 3 participants
of the DYS/COMBO group resulting in an n=10 for those
analyses.
 Responses
Pearson Product Moment Correlations revealed the following significant
relationships:
 The percentage of common words identified as real words correlated
significantly with the CELF expressive score (r = .509; p < .05).
“checklist percentage difference” score correlated significantly
with the CELF expressive score (r = .560; p < .01).
25th
Experimental Tasks
 A 90-item nonword repetition task of 2, 4, and 6 syllable
nonwords (a modification of Gupta’s 2003 task) was
administered to all participants. Participants repeated digitally
recorded productions of these nonwords.
DISCUSSION
 The
 For



who scored at or below the
percentile on the
Letter-Word Identification or the Word Attack subtest of the
Woodcock-Johnson were included in the “DYS/COMBO” group.
CELF scores were allowed to vary within this group.
To compare a group of children with SLI only
(SLI) to a group of children with decoding
deficits either alone or in combination with SLI
(DYS/COMBO) on two tasks: nonword
repetition (NWR) and a word/nonword
discrimination task.
HYPOTHESES
Groups
 Participants were administered the Reading portion of the
Woodcock-Johnson Achievement Tests (Woodcock, McGrew &
Mather, 2001) and the Clinical Evaluation of Language
Fundamentals, 4th edition (CELF; Semel, Wiig & Secord, 2003).
 Participants
PURPOSE

RESULTS
Accuracy in Percent

METHOD (cont’d)
100
90
80
70
60
50
50
60
70
80
90
Letter-Word Identification Standard Scores
Figure 2. The Relationship Between Letter-Word
Identification Subtest Standard Scores and Nonword
Repetition Total Scores, r = .549; p < .05
100
The presenters gratefully acknowledge Summer
Windels for her help with data analysis.
This study was funded by an NIH/NIDCD research
grant awarded to the second author (R03
DC006827-01).