Acquisition of Speech Prosody in a Non-native Tone Language by Children With and Without Autism Spectrum Disorder

Children with autism spectrum disorder (ASD) often show abnormal speech prosody. Tonal languages can pose more difficulties as speakers need to use acoustic cues to make lexical contrasts while encoding the focal function, but the acquisition of speech prosody of non-native languages, especially tonal languages has rarely been investigated.

This study aims to fill in the aforementioned gap by studying prosodic focus-marking in Mandarin by native Cantonese-speaking children with ASD (n = 25), in comparison with their typically developing (TD) peers (n = 20) and native Mandarin-speaking children (n = 20). Natural prosodic marking of different types of focus was elicited by picture-based prompt questions, recorded and analyzed acoustically.

The autistic children made use of fewer acoustic cues and produced less evident on-focus expansion in these cues than TD, especially the native-Mandarin speaking peers. They also demonstrated a clear preference to on-focus expansion than to post-focus compression. These children, together with their native Cantonese-speaking peers, also hyper-performed in tone realization, prioritizing lexical prosody over focus marking. Such hyper-performance may further limit their use of prosodic cues in focus marking. However, the difficulties the autistic children faced in the acquisition of speech prosody in a non-native tone language, though found, are not more than those they face in their mother tongue.

Multilingual exposure may help the autistic children master the use of some focus marking strategies though they still need interventions to help them to implement their focus-marking knowledge more sufficiently in both native and non-native languages.