Divergent Cognitive-Linguistic Mechanisms in Mandarin Sentence Recognition: The Impact of F0 Contour and Noise in Children With and Without Developmental Language Disorder

Purpose
Developmental language disorder (DLD) is a neurodevelopmental disorder that affects speech and language processing. This study aimed to investigate how syllabic fundamental frequency (F0) contours and background noise affect Mandarin sentence recognition in children with DLD and identified cognitive-linguistic predictors of their performance.

Method
Twenty-one children with DLD and 23 age-matched typically developing (TD) peers completed an open-set sentence recognition task crossing F0 (natural vs. flat) and listening condition (quiet vs. speech-shaped noise). Accuracy was scored at syllable and sub-syllabic levels (onset, rime, and tone).

Results
Results showed that flat F0 reduced sentence intelligibility for both groups, with larger effects in noise. Importantly, children with DLD performed worse than TD peers only when F0 was flattened. At the sub-syllabic level, onset, rime, and tone accuracy deteriorated under flat F0 and noise, particularly in DLD. Hierarchical regressions revealed dissociable predictors: verbal working memory (WM) explained a large and significant portion of variance in DLD (notably in the natural-F0, quiet condition), whereas nonverbal IQ predicted TD performance across adverse conditions; language measures were not significant predictors for both groups.

Conclusions
These findings indicate that Mandarin-speaking children with DLD rely on intact F0 contours as a compensatory mechanism, a strategy that becomes fragile when prosodic or signal quality is degraded. Divergent cognitive pathways underscore the need for ecologically valid assessment and targeted supports.