Mandarin non-interrogative <i>wh</i> -words distinguish between children with Developmental Language Disorder and language-impaired autistic children

Language profile resemblance between autistic children who are language-impaired and children with Developmental Language Disorder (DLD) gives rise to misdiagnosis of the two conditions. Aiming to better understand the underlying causes of language impairments in autism language impaired (ALI) and DLD, the present study adopts a question-statement task to investigate the ability to determine the non-interrogative interpretation of Mandarin wh-words on the basis of syntactic-semantic cues and prosodic cues. The results show that both the ALI and the DLD groups have difficulty using the syntactic-semantic cues to access the non-interrogative interpretations of Mandarin wh-words. However, only the performance of the ALI group correlates with their extralinguistic cognitive ability. Furthermore, the two groups performed differently in using the prosodic cues: the DLD group scores significantly higher than the ALI group on the perception of the prosodic cues. The different linguistic profiles found in the current study suggest that ALI may not simply be a comorbidity of autism and DLD, as has often been proposed. The study’s findings also have the potential to improve diagnostic procedure and to increase accuracy of differential diagnosis in children.