Bilingualism in children with developmental disorders: A narrative review.

Children with developmental disabilities (DD) often need and sometimes opt to become bilingual. The context for bilingual acquisition varies considerably and can impact outcomes. In this first article of the special issue, we review research on the timing and amount of bilingual exposure and outcomes of either direct language intervention or educational placements in three groups of children with DD: Specific Language Impairment (SLI), Autism Spectrum Disorders (ASD), and Down syndrome (DS). Children with SLI have been studied more than the other two groups. Findings showed that, on the one hand, the communication skills of simultaneous bilinguals and matched monolinguals with DD were similar for all groups when the stronger language or both languages of the bilingual children were considered. On the other hand, similar to typically developing children, sequential bilinguals and matched monolinguals with SLI (other groups not studied) differed on some but not all second language (L2) measures; even after an extended period of exposure, differences in L2 outcomes were not completely resolved. There is emerging evidence that the typological similarity of the languages being learned influences L2 development in sequential bilinguals, at least in children with SLI. Increasing the frequency of exposure seems to be more related to development of the weaker language in bilinguals with DD than their stronger language. Language intervention studies show the efficacy of interventions but provide little evidence for transfer across languages. In addition, only one (unpublished) study has compared the language and academic outcomes of children with DD in different language education programs. Research on bilingual children with DD in different educational settings/programs is limited, probably as a result of restricted inclusion of these children in some educational settings. We argue for the implementation of full inclusion policies that provide increased access to dual language programs for children with DD and access to a complete range of support services.