Bilingual exposure across contexts: Association with first and second language vocabulary in autistic and neurotypical children

This study investigated how bilingual exposure relates to first language (L1) and second language (L2) receptive vocabulary in autistic and neurotypical children in Hong Kong, and how bilingual exposure across home, school and community contexts is associated with vocabulary outcomes. A total of 179 children (87 autistic, 92 neurotypical) who acquired Cantonese as L1 and English as L2, completed standardized Cantonese and English receptive vocabulary tests, alongside background measures of nonverbal IQ, working memory, and socioeconomic status. Parents reported children’s current Cantonese and English exposure across contexts. Autistic and neurotypical children showed similar total Cantonese exposure, but autistic children received significantly less English exposure, particularly at home and school. Bilingual exposure was not associated with L1 vocabulary in either group, whereas greater bilingual exposure was positively associated with L2 vocabulary in both groups, with no evidence that autistic children benefited less from bilingual exposure. Furthermore, L2 exposure at home and school, but not in the community, was associated with stronger L2 vocabulary. The results highlight the importance of considering both the amount and context of language exposure in understanding bilingual development in autism.