Linguistic and communicative competence in bilingually-exposed children with autism spectrum disorders

Submission note: A thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Psychology in Clinical Psychology to the School of Psychological Science, Faculty of Science, Technology, and Engineering, La Trobe University, Bundoora.

Despite many children with Autism Spectrum Disorders (ASD) growing up in bilingual environments, only limited research currently exists investigating the impact of bilingualism on the language development of young children with ASD. Existing research has predominantly concluded that bilingual exposure is not detrimental to the language development of young children with ASD. The present research aimed to extend on the limited number of studies to date to determine the impact of parental bilingualism by using a combination of language and communication measures in young children with ASD who had either monolingual or bilingual exposure. The participants, aged 2 to 5 years, were 38 children with ASD; 20 monolingually-exposed and 18 bilingually-exposed. Children’s language and communication skills (in English and also in the parental native language for those with bilingual exposure) were assessed using standardised direct testing, parent report and direct observation of spontaneous speech and communication. Results revealed inconsistencies across measures in relation to English receptive vocabulary. Specifically, results from direct assessment suggested no differences between groups in English receptive language ability, while parent report measures suggested monolingual children to have larger receptive vocabularies than bilingually-exposed children. The groups were also found to differ significantly in relation to variables derived from the direct observation of spontaneous language and communication samples, including gesture use, mean length of utterance, and number of different words produced. Overall, monolingual children were found to have larger English expressive vocabularies, compared to the bilingually-exposed children. Only a small number of bilingually-exposed children were found to be successfully acquiring both English and their parental native languages, with the remainder demonstrating clearly dominant English language skills.