I've been thinking about deafness a good deal recently because I have a deaf character in a story I'm working on. Deafness fascinates me because it is, in one sense, a medical problem - caused by nerve defect, for example, or accident, or abuse of the ears over a long period of time - but in another sense it is a badge of membership in a language community.
The difference between auditory languages and visual languages is sometimes called a "channel" difference. Channel effectively means which sensory pathway is chosen for the language conduit, and in past entries I've discussed this a little; I know I've mentioned chemical scent languages a couple of times.
In a sense, by being born without hearing or becoming deaf, a person loses one channel. They then have two choices: attempt to "cure" the deafness medically, or use another language channel. In school I saw a fascinating video about cochlear implants, which can cause some deaf people to begin to hear. In that video was one woman who lost hearing as an adult, and she definitely felt rescued by the implant which restored her hearing. Then there were the children, and therein lay the conflict.
A pair of hearing parents with a deaf child had no hesitation about "restoring" the child's hearing.
A pair of deaf parents with a deaf child did not want to take away the deafness which was part of what defined her, didn't want in a sense to evict her from the cultural community to which they belonged.
Part of what entered into their decision was having someone assess the speech of other children who had had cochlear implants, and tell them whether they "sounded deaf" or not. They made their decision to forego the implant because they felt that giving her hearing would oust her from true membership in the deaf community, and they weren't convinced that it would give her true membership in the hearing community.
This last one is an issue of brain plasticity, or the ability of the brain to learn new language information. A rule of thumb on child language states effectively that the brain loses the ability to acquire nativelike phonological ability (i.e. pronunciation) at about age 6; grammar not until about age 13. Thus the later a child receives a cochlear implant, the more difficulty that child will have in processing the sound and turning that into natural-sounding auditory language.
Personally I thought it a shame that the child in question should miss out on hearing all the wonderful sounds of the world - but on the other hand, I understood the parents' cultural point of view.
I want to talk also about sign language a little, but I'm going to have to save that for another post.