Bilingualism in children with autism spectrum disorder: Making evidence based recommendations.

Over half of the world's population speaks more than one language (Ansaldo, Marcotte, Scherer, & Raboyeau, 2008), and thus many children with autism spectrum disorder (ASD) will be raised in bilingual families. ASD is among the most common neurodevelopmental disorders, affecting one in 68 children (Wingate et al., 2014). It is characterized by deficits in social communication, as well as restrictive, repetitive, and stereotyped behaviors (DSM-5; American Psychiatric Association, 2013). Since many children with ASD also present language deficits (Rapin & Dunn, 1997), it is often recommended that bilingual families of children with ASD focus on the language of schooling and refrain from using the family's home language with their child in order to avoid language confusion or further language delays (Jegatheesan, Fowler, & Miller, 2010). Recent research has questioned whether these recommendations are well founded. Does bilingualism truly increase language delays in children with ASD? Will bilingualism lead to language confusion in these children? What are the implications of recommendations that discourage bilingualism, both for the child's development and for the family's overall well-being? The goal of this paper is to answer these important questions by reviewing the literature available in the field of autism specifically and within the broader field of bilingual language development. By doing so, we aim to assist professionals working in the field of ASD in providing recommendations that are evidence-based to bilingual families affected by ASD.Bilingualism in Neurotypical ChildrenBroadly speaking, bilingualism refers to an individual's ability to communicate in two languages. Bilinguals can be placed on a continuum that ranges from individuals who know a few phrases in a second language to those who are equally proficient in their two languages. When speaking about bilingualism, the term majority language is used to refer to the language spoken by the majority of individuals in a given environment, while the terms minority, home, or heritage language refer to the language spoken by a minority of speakers in a given community. For many bilingual speakers, their languages are closely linked to the culture associated to each language they speak (Kremer-Sadlik, 2005). Given the importance and, for some families, the necessity of bilingualism, multiple studies have examined the effects of bilingualism on language development in neurotypical bilinguals, and more recently, in children with language, cognitive and/or developmental delays, including children with ASD. Overall, research suggests that neurotypical children can become proficient in their two languages, even attaining abilities similar to those of monolinguals. That said, although bilingual children share many similarities with their monolingual peers, bilingual children should not be considered to be two monolinguals in one child. Indeed, several differences exist between bilinguals and monolinguals, particularly during the first few years of language acquisition. The following paragraphs will address these issues and discuss some of factors that influence language acquisition and proficiency in neurotypical bilingual children.Several factors including (a) age of language acquisition, (b) amount of language input, and (c) social factors tied to the language context can affect the pace of language development in one or both of a bilingual child's languages (MacLeod, CastellanosRyan, Parent, Jacques, & Seguin, 2017; MacLeod, Fabiano-Smith, Boegner-Page, & Fontolliet, 2013; Thordardottir, 2011). When addressing differences in age of language acquisition, bilinguals are often divided into two groups reflecting the age at which they began to learn their second language. Simultaneous bilinguals are individuals who acquired both languages more or less at the same time, usually before the age of 3 years, whereas sequential bilinguals are those who acquired their second language after having acquired their first language, usually after 3 years of age (Paradis, Genesee, & Crago, 2011), although there is considerable variability within the literature with regard to the age cut-off that defines these two groups (see Paradis et al. …