Language and Repetition Performance in Autism Spectrum Disorder Versus Developmental Language Disorder: Evidence From...

Autism spectrum disorder (ASD) is a neurodevelopmental condition characterized by persistent differences in social communication and interaction, as well as restricted and repetitive patterns of behavior, interests, or activities. Language difficulties are common in autism and can affect multiple domains, including phonology, morphology, syntax, semantics, and pragmatics. This study examined the language and repetition skills of Turkish-speaking autistic children (diagnosed with ASD), children with developmental language disorder (DLD), and typically developing (TD) peers. Ninety children aged 5-9 years participated: 30 autistic children, 30 children with DLD, and 30 TD children. Language abilities were assessed using the Turkish School Age Language Development Test (TODİL), the LITMUS Turkish Sentence Repetition Test (LITMUS-TR), and the Turkish Nonword Repetition Test (TAST). The TD group scored significantly higher than both clinical groups across all measures. In direct comparisons between the clinical groups, autistic children had lower scores than children with DLD on several morphosyntactic and lexical-semantic measures. After Bonferroni correction, only morpheme completion (TODİL BT) differed significantly between the groups; associated vocabulary (TODİL IS) and word description (TODİL SB) showed smaller differences that did not reach the Bonferroni-adjusted significance threshold. The two clinical groups showed similar performance on picture vocabulary (TODİL RS), sentence comprehension (TODİL CA), sentence repetition (TODİL CT; LITMUS-TR), and nonword repetition (TAST). The findings indicate specific areas of relative difficulty in morphosyntactic and lexical-semantic processing among autistic children in this sample, alongside broadly similar performance to children with DLD on other sentence-level and repetition measures. These results suggest the potential value of tailored, evidence-based interventions that consider autistic children's individual language profiles, while also taking into account broader cognitive and executive functioning needs.