Two Are Better Than None: In Defense of Bilingualism for Deaf Children
Bimodal bilingualism (knowing both a sign language and a spoken language) is an alternative approach that may both minimize the risk of language deprivation and maximize the benefits of cochlear implantation. Since sign language is fully accessible to deaf children, every child will have full command of at least one natural language under a bimodal bilingual approach.
The persistent belief that using sign language will lead to poorer spoken language outcomes is based on studies of manual communication systems that are derived from spoken English. Such studies do not measure the impact of bimodal bilingualism, which uses natural sign languages.
Another concern is that sign language will usurp brain tissue needed for speech, thus hindering speech development. However, these arguments are not informed by actual outcomes in bimodal bilinguals.
New data show that bimodal bilingual CI users develop on par with hearing peers, repeatedly outperforming monolingual CI users on spoken language measures. These studies are small, but they are important given strong claims in the literature about sign language being putatively harmful. Increasing the scale of these studies is an urgent priority for future research.
There is far more to child development than the ability to hear and speak. Unfortunately, many deaf children experience delays or disturbances in other developmental domains, including cognition, academics, social development, and mental health. These problems are commonly attributed to deafness itself; however, deaf children with early exposure to sign language generally do not exhibit these problems. Thus deafness itself is not the root cause; instead, the key issue may be a lack of early exposure to accessible natural language. Direct tests of this hypothesis are another key priority for future research.
Implementing bimodal bilingualism will require innovative solutions to serious practical challenges. However, we have solved more difficult challenges in the past, and can do so again as evidence accumulates in favor of bimodal bilingualism for deaf children.