Verified by 
Post written by François Grosjean.
All language scientists have a wow moment in their profession. Mine was when I was introduced to sign language and to the world of the Deaf. I was simply overwhelmed by the beauty of this visual gestural language as well as by the history of Deaf people.
Many myths still surround sign language such as that it is universal (in fact, there are as many sign languages as there are Deaf communities), that it is speech on the hands (as a visual gestural linguistic system it is in many ways very different from a spoken language), that it only expresses concrete notions (one simply needs to look at sign poetry to understand how very rich and symbolic it can be), and so on.
The users of sign language are often bilingual - one language is sign language (e.g. American Sign Language) and the other is the language of the hearing majority (e.g. English), often in its written form. This is termed bimodal bilingualism. Deaf bilinguals share many similarities with hearing bilinguals: they are diverse (some are Deaf, some are hard of hearing, some even are hearing), many do not consider themselves to be bilingual (see a post on this), they use their languages for different purposes, in different domains of life, with different people (as explained here), and they communicate differently depending on whether they are addressing monolinguals or bilinguals.
There are also aspects that are specific to the bilingualism of the Deaf one of which is that there is still no widespread acceptance that they have the right to be bilingual. Thus, many Deaf children in the world are not given the chance of mastering both a sign language and an oral language from their earliest years on. A purely oral language education is preferred for them even though many of them may not adequately master the oral language. As a consequence, they will have problems communicating with many of those who matter most in their lives.
And yet, recent research has shown the many advantages of allowing Deaf children to know and use both a sign language and an oral language. It is the optimal combination that will allow these children to meet their many needs, that is, communicate early with their parents (first in sign and then, with time, also in the oral language), develop their cognitive abilities, acquire knowledge of the world, communicate fully with the surrounding world, and acculturate into their two worlds.
Depending on the child, the two languages will play different roles: some children will be dominant in sign language, others will be dominant in the oral language, and some will be balanced in their two languages. Just like other bilingual children, they will use their languages in their everyday lives and they will belong, to varying degrees, to two worlds - in this case, the hearing world and the Deaf world.
It is still quite common for some professionals involved with deafness (doctors, speech-language pathologists, teachers, etc.) as well as for some parents to believe that the knowledge of sign language will hinder the development of the oral language in Deaf children. This is unfortunate as it is now well accepted that a first language that has been acquired normally, be it spoken or signed, will greatly enhance the acquisition and use of a second language.
In the case of Deaf children, whether they have a cochlear implant or not, sign language can be used early on to communicate while the oral language is being acquired; it can be used to express emotions, to explain things as well as to communicate about the other language; and linguistic skills acquired in sign such as discourse rules and even general writing skills, acquired through sign writing, can be transferred to the oral language. It has been shown that the better the children's skills are in sign language, the better they will know the oral language.
As I state in a short text on this issue that has been translated into some 35 languages in a collaborative project with Gallaudet University (see here), one never regrets knowing several languages but one can certainly regret not knowing enough, especially if one's own development is at stake.
References
Grosjean, F. (2010). Bilingualism, biculturalism, and deafness. International Journal of Bilingual Education and Bilingualism, 13 (2), 133-145.
Plaza-Pus, C. and Morales-López, E. (2008). Sign Bilingualism: Language development, interaction, and maintenance in sign language contact situations. Philadelphia & Amsterdam: John Benjamins.
"Life as a bilingual" posts by content area: http://www.francoisgrosjean.ch/blog_en.html
François Grosjean's website: www.francoisgrosjean.ch
Photo by Dieter Spörri. Kalender fûr Gehörlosenhilfe 2002. Hallwag Medien, Bern, Switzerland.
