Bimodal bilingualism

Bimodal bilingualism is an individual or community's bilingual competency in at least one oral language and at least one sign language, which utilize two different modalities. An oral language consists of a vocal-aural modality versus a signed language which consists of a visual-spatial modality.^[1] A substantial number of bimodal bilinguals are children of deaf adults (CODA) or other hearing people who learn sign language for various reasons. Deaf people as a group have their own sign language(s) and culture that is referred to as Deaf,^[2] but invariably live within a larger hearing culture with its own oral language. Thus, "most deaf people are bilingual to some extent in [an oral] language in some form".^[3] In discussions of multilingualism in the United States, bimodal bilingualism and bimodal bilinguals have often not been mentioned or even considered. This is in part because American Sign Language, the predominant sign language used in the U.S., only began to be acknowledged as a natural language in the 1960s (in discussions of bimodal bilingualism in the U.S., the two languages involved are generally ASL and English). However, bimodal bilinguals share many of the same traits as traditional bilinguals (those with competency in at least two spoken languages), as well as differing in some interesting ways, due to the unique characteristics of the Deaf community. Bimodal bilinguals also experience similar neurological benefits as do unimodal bilinguals (see Cognitive effects of bilingualism), with significantly increased grey matter in various brain areas and evidence of increased plasticity as well as neuroprotective advantages that can help slow or even prevent the onset of age-related cognitive diseases, such as Alzheimer's and dementia.