Bilingual parents of children with autism spectrum disorder often decide to speak only one language around their child because of advice from child development professionals who believe that exposure to two languages might further limit the child’s communication skills. Two recent studies challenge that assumption.
One study tested the vocabulary size of 14 bilingual (English-Mandarin/Cantonese) and 14 English-monolingual young children with ASD (aged 3-6). Bilingual children had a larger total vocabulary than monolingual children. When translation equivalents (two words in each language with the same meaning) were counted only once, the vocabularies of both bilingual and monolingual children were not significantly different. Both groups had equivalent scores on all but one measure of language and vocabulary, including English production vocabulary, conceptual production vocabulary, and vocabulary comprehension.
The second Canadian study found similar results in a slightly larger group of children (45 bilingual and 30 monolingual children with an average age of around 5). Languages covered were diverse: French, English, Chinese, Farsi, Hebrew, Italian, Romanian, Spanish and Tamil. Bilingual children were divided into those who were exposed to both languages from infancy, and those who were exposed later (the cut-off was 12 months, but in general changes in the language environment occurred much later: on average, children in the former group were bilingually-exposed for the first 25 months; children in the latter group were monolingually-exposed for the first 31 months). Eleven children were trilingual. In order not to introduce sampler bias, non-verbal children were not excluded — seven participants spoke fewer than 10 words, of whom two were nonverbal.
There were no significant differences between the three groups at a language level, although monolingual and bilingual children exposed from infancy consistently scored higher than bilingual children exposed from a later age. Also, children exposed to two or more languages from infancy scored significantly higher than both groups on social interaction, and those exposed later were worst of the three groups. These differences probably reflect various social variables underlying the different language experiences.
The main reason for the belief that autistic children are better not ‘burdened’ with an additional language is because of their language difficulties. These studies are not saying that a child with ASD raised in two languages will be equally fluent with both. In the second study, second language vocabularies were much smaller than their dominant language vocabularies. But that’s not the point. Whether or not there is any general cognitive advantage in bilingualism for this group, as there is for normally-developing children, remains to be determined. But there is a clear message that parents of ASD children can take on board: if your family is bilingual, relax and enjoy interacting with your ASD child in your language of choice.
 . Brief Report: An Exploratory Study of Lexical Skills in Bilingual Children with Autism Spectrum Disorder. Journal of Autism and Developmental Disorders [Internet]. 2011 . Available from: http://www.springerlink.com/content/e23p3j601u11m024/
 . The Impact of Bilingual Environments on Language Development in Children with Autism Spectrum Disorders. Journal of Autism and Developmental Disorders [Internet]. 2011 . Available from: http://www.springerlink.com/content/9318n42233747147/