Language and communication skills in multilingual children on the autism spectrum: A systematic review.

The review included only group comparison studies, so single-case and qualitative accounts of multilingual autistic children were not synthesised. All eligible studies were included regardless of study quality, so weaker studies were not separated from stronger ones. Eleven of 22 publications used overlapping participant samples, which limited how much the findings could be combined. Many studies excluded children with intellectual disability, exposure to more than two languages, or complex communication needs, so the findings do not cover the whole autism spectrum. Only seven studies reported scores for both languages, and many used single-language comparisons, which may understate bilingual children's vocabulary. Phonology and pragmatics were severely understudied, including skills often relevant to autistic children's communication. Most included studies were cross-sectional group comparisons rather than treatment studies, so the review cannot show what a bilingual therapy environment would do.

The authors declared no potential conflicts of interest and received no financial support for the research, authorship, or publication of the article.

Do not read lower vocabulary scores as proof that multilingual exposure harms language. Twelve studies reported scores for only one language, and the review found no evidence of negative effects.