Purpose: Developmental language disorder (DLD) is a multifaceted disorder. Recently, interest has grown in prosodic aspects of DLD, but most investigations of possible prosodic causes focus on speech perception tasks. Here, we focus on speech production from a speech amplitude envelope (AE) perspective. Perceptual studies have indicated a role for difficulties in AE processing in DLD related to sensory/neural processing of prosody. We explore possible matching AE difficulties in production.
Method: Fifty-seven children with and without DLD completed a computerized imitation task, copying aloud 30 familiar targets such as "alligator." Children with DLD (n = 20) were compared with typically developing children (age-matched controls [AMC], n = 21) and younger language controls (YLC, n = 16). Similarity of the child's productions to the target in terms of the continuous AE and pitch contour was computed using two similarity metrics, correlation, and mutual information. Both the speech AE and the pitch contour contain important information about stress patterning and intonational information over time.
Results: Children with DLD showed significantly reduced imitation for both the AE and pitch contour metrics compared to AMC children. The opportunity to repeat the targets had no impact on performance for any group. Word length effects were similar across groups.
Conclusions: The spoken production of multisyllabic words by children with DLD is atypical regarding both the AE and the pitch contour. This is consistent with a theoretical explanation of DLD based on impaired sensory/neural processing of low-frequency (slow) amplitude and frequency modulations, as predicted by the temporal sampling theory.
Supplemental material: https://doi.org/10.23641/asha.27165690.