Multilingual Language Environments and ASD: Relationships Between Amount of Language Exposure and Language Proficiency

Background: It is commonly thought that children with communication disorders should only be exposed to one language, though research does not indicate additional language delays from bilingual exposure (e.g. Ohashi et al., 2012). To gauge the impact of bilingual environments on language development in Autism Spectrum Disorders (ASD), it is critical to understand the relationship between amount of language exposure and language proficiency. A recent study found that expressive vocabulary (by parent report) in the second language was highly correlated with the amount of recent exposure to that language in bilingual children with ASD (Hambly and Fombonne, 2014), suggesting that children with ASD learn a 2^nd language when given adequate exposure. However, relationships between exposure and proficiency in different language domains (e.g., vocabulary, morphology, sentence repetition) for children with ASD in bilingual environments have not been studied.

Objectives: We examine relationships between amount of language exposure and language proficiency in children with ASD with varying degrees of exposure to French via direct assessment on standardized measures. Based on Hambly and Fombonne (2014) we hypothesize that amount of exposure to the target language will be highly correlated with proficiency in that language. We explore the relationship between amount of exposure and two previously unstudied expressive language skills: morphology and sentence repetition, as well as receptive vocabulary.

Methods: Twenty five 5- to 10-year-old children with ASD were included. Participants were exposed to varying amounts of French throughout their lifetime, ranging from French monolinguals to balanced bilinguals in French and another language (English or Spanish). Parents completed a detailed language exposure questionnaire. Following Thordardottir’s (2011) methodology, each child was classified in one of five French exposure groups (e.g., 0-20%, 80-100%). Across these 5 groups children were matched on nonverbal IQ, chronological age and socio-economic status (via maternal education). Language proficiency was assessed using the morphology and sentence repetition sub-tests of the French version of the Clinical Evaluation of Language Fundamentals (CELF-4; Semel et al., 2003). Vocabulary was evaluated through the French version of the Peabody Picture Vocabulary Test (EVIP; Dunn, Theriault-Whelan, & Dunn, 1993).

Results: Groups did not differ significantly on nonverbal IQ (p=.18), chronological age (p=.85) or SES (p=.08). We found marginally significant correlations on the expressive language measures of morphology (r=.40, p=.045) and sentence repetition (r=.39, p=.056). A strong, significant correlation was found for receptive vocabulary (r=.59, p=.002).

Conclusions: We found correlations between language exposure and proficiency on a range of standardized measures. As reported for typical development (e.g., Pearson et al., 1997), amount of language exposure was not perfectly correlated with language skills and other factors play a role, especially for expressive language. Some children who had low levels of exposure to the target language still performed in the normal range on language measures. Additional analyses will explore relationships between exposure and both parent and observer-rated proficiency in French. These results support previous findings suggesting that children with ASD acquire two languages when provided with optimal opportunities to do so.