Lexical diversity and lexical skills in children who stutter.
Courtney Luckman, Stacy A Wagovich, Christine Weber and 4 others
PMID 32058092WHAT IT FOUND
Children who stutter scored lower on standardized vocabulary tests than matched peers, but showed no difference in lexical diversity during spontaneous conversation.
Both groups remained within the normal range. This suggests subtle weaknesses appear in structured testing, not natural speech.
Key findings
01Children who stutter achieved significantly lower expressive and receptive standard scores on vocabulary tests compared to matched typically-fluent peers.
02There were no significant differences in lexical diversity measures (NDW, VocD, TTR, TTR50, MATTR) between the two groups in spontaneous language samples.
03Lexical diversity measures did not correlate significantly with expressive vocabulary test scores after correction for multiple comparisons.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
The wide age range (25 to 100 months) makes it difficult to determine if vocabulary differences preceded stuttering onset or emerged after. Data was pooled from multiple labs with varying language sample elicitation methods (e.g., clinician-child vs parent-child interactions), which may introduce variability. Many studies in the pool had excluded children who did not perform within normal limits on language screening, potentially biasing the sample toward higher-functioning CWS. The study used a Bonferroni correction for multiple comparisons, which is conservative and may increase the risk of Type II errors (missing real small differences).
Declared interests
The research was supported by the National Institutes of Health (NIH) and other US government and non-US government grants. The authors declared no conflicts of interest.
The easy way to misread this
Do not interpret the significant difference in standardized test scores as evidence of a clinical language disorder. Both groups scored within the normal range, and the lack of difference in spontaneous speech suggests the deficit is task-specific rather than a fundamental lack of lexical knowledge.