[One of 50 articles written and published for Demand Media in 2013. Published version here.]
Ninety percent of children born to deaf parents have normal hearing. Not all deaf adults converse in sign language, but in homes where they do, children grow up bilingual. American Sign Language is often their first language. Because spoken language is so common, children easily acquire speech through interaction with other family members, playmates, day care, movies and television. Dr. Laura-Ann Pettito, a neuroscientist doing research on the biological basis of language, says “Study after study showed that for every level of language organization, signed languages and spoken languages were using the identical brain tissue.”
American Sign Language
ASL is a complete language, distinct from English, with its own grammar, sentence structure, expression of tenses and time. It is a three-dimensional language, which enables conceptual constructs not available to spoken language. Children — deaf and hearing alike — who learn ASL as their first language arrive at common linguistic development milestones at the same pace that spoken language milestones are reached. At 3 to 6 months, they are “fingerbabbling” in imitation of finger-spelling, At 6 to 12 months, they will gesture. First signed words appear at about 8 months, with 10 or more understood and expressed signs at 12 months. In a paper titled “Milestones of Language Development,” researchers report that, “The phonology, syntax, semantics, morphology and pragmatic aspects of language are acquired around 4 years of age whether the parental input is in sign or spoken language”
Bilingualism
It is now widely recognized that bilingualism boosts mental agility and flexibility. As Pettito states, “It’s almost as if the monolingual child’s brain is on a diet and the bilingual child’s brain stretches to the full extent and variability that Mother Nature gave it to use language and exploit human language.” For children, the process of learning signed and spoken language at the same time is natural and intuitive. Bilingual children in deaf households respond to ASL in ASL, to speech with speech, and switch between them as needed. Because this requires more active monitoring of their environment, they do monitoring tasks better and more efficiently than their monolingual peers.
Deaf Children
Early exposure to English is important for deaf children. A helpful tool in this area is the availability of captions and subtitles in movies and televisions. Early recognition of the differences between English and ASL grammar supports strong reading and writing skills later. Parental involvement matters, too. By sharing children’s books, the text can be signed and read in English, providing a bridge of understanding between both communication modes. In a 2000 study titled “American Sign Language and Reading Ability in Deaf Children,” a strong correlation was found between deaf children of deaf parents and higher reading achievement scores. Deaf parents have no need to “get up to speed” on the use of ASL as a language, so ASL development in their children begins immediately. This early acquisition of language facilitates learning English and reading skills later.
Children of Deaf Parents
Children of deaf adults have a special role in the deaf community. As hearing children of deaf parents, they learn to juggle relationships with hearing and deaf individuals, institutions, cultural norms and languages. They might have deaf or hearing siblings, or both; they often grow up with both deaf and hearing friends. They are not only bilingual, they are bicultural. Among professional sign language interpreters, children of deaf adults are common. Growing up with deaf parents gives them a native’s grasp for the subtleties and nuances of ASL, and their grasp of both English and ASL is strong enough that they can earn a living interpreting between them.