Expressive language growth among young children who do and do not stutter

Previous research on language development differences in children who stutter (CWS) compared to their non-stuttering peers (CWNS) has yielded mixed results. Few studies have analyzed spontaneous speech samples from both groups studied over time. This study aims to examine expressive language by analyzing growth in expressive syntactic complexity. We also explored the relationships among syntactic complexity growth, recovery and persistence status, and stuttering severity.

Conversational speech samples were collected annually over 3-4 years from 100 CWS (32 female) and 85 CWNS (36 female), aged 3;0-5;11 at the study's start. These recorded samples were analyzed using the Index of Productive Syntax (IPSyn). We employed hierarchical linear regression modeling and Empirical Bayes' posterior means to assess group differences and individual growth trajectories over time.

Overall, both groups exhibited similar growth in syntactic complexity. Among CWS, there was no notable difference in syntactic complexity growth between those who recovered from stuttering and those who persisted. In children who recovered, higher complexity of expressive syntax was significantly associated with lower stuttering severity. Additional analyses suggested that CWS tended to have lower scores on the IPSyn Verb Phrase subscale compared to CWNS.

In this study, development in expressive syntactic complexity did not distinguish CWS from CWNS, nor did it differentiate between children who recovered from stuttering and those who persisted. However, in children who recovered, greater expressive syntax scores were linked to reduced stuttering severity, suggesting that more mature language ability may play a protective role in stuttering recovery.