Verbal and Motor Skills in Mandarin-Speaking Children With Developmental Language Disorder: Do Co-Occurring Motor Deficits Matter?

BACKGROUND: Children with developmental language disorder (DLD) often show motor coordination difficulties. Yet, it remains unclear whether children with DLD who have motor difficulties represent a distinct subtype with different verbal profiles compared with children with DLD whose motor coordination falls within the typical range. This study examined the verbal and motor profiles of Mandarin-speaking school-age children with DLD, comparing subgroups with and without co-occurring developmental coordination disorder (DCD). METHOD: Thirty-five children with DLD and 59 typically developing (TD) children completed assessments of vocabulary, syntax, verbal short-term memory (STM), and motor coordination. Group comparisons of specific motor components (manual dexterity, aiming and catching, and balance) and overall motor coordination were conducted between the full DLD sample and the TD group, followed by subgroup comparisons among the DLD-only, DLD + DCD, and TD groups. RESULTS: Children with DLD showed widespread deficits in motor coordination. Subgroup analyses indicated that the DLD + DCD group scored significantly lower than both the DLD-only and TD groups across all motor components, whereas the DLD-only group also showed reduced overall motor coordination relative to TD peers. For verbal abilities, the DLD + DCD group scored lower than the other two groups across all verbal domains, whereas the DLD-only group showed weaknesses in syntax and verbal STM but not in vocabulary. Finally, overall motor coordination significantly predicted verbal abilities within the DLD sample after controlling for age and nonverbal IQ. CONCLUSIONS: Motor coordination difficulties are common in DLD and may signal a more severe verbal profile. These findings point to potentially interrelated developmental and neurocognitive connections between motor and verbal domains.