Bilingual cognitive advantages in multilingual and multimodal deaf and hard-of-hearing children and adults

A sizable proportion of deaf and hard-of-hearing (DHH) people are multilingual, either through use of language that involves more than one modality (i.e., signing and speaking/listening) or the use of two or more languages within the same modality. There is a constantly evolving body of research that describes cognitive differences between monolinguals and multilinguals, the majority of which examines people without hearing loss who use more than one spoken language. Much less attention has been paid to cognitive differences associated with multilingualism in people who are DHH and people who use signed languages. This chapter briefly summarizes research describing differences in
cognition between monolingual and multilingual oral language users without hearing loss, and then focuses on research comparing bimodal bilinguals (both DHH and hearing) with monolinguals and/or spoken-language multilinguals. Areas of cognition that are discussed include language processing, inhibition and selective attention, task switching, and working memory. In general, findings were inconclusive or inconsistent regarding a bilingual advantage or disadvantage in cognitive processes for bimodal bilinguals. However, the evidence base was limited and further research is essential if stronger
conclusions are to be drawn.