It comes from the musical term. The idea is that when hearing children are born to deaf parents, it is the closing of a familial era. Just as a musical composition has a coda that brings it to a close, a coda that can stand on its own as a piece of music, a hearing child is not only a part of the culture and heritage of the Deaf community, but can stand on his/her own apart from the community.
The way that I like to put it is this:
My parents (the composition) are a masterpiece, and I am the closing out that particular piece, along with my two sisters. But, standing alone, I have a unique culture in that I have a mixture of both hearing and Deaf culture. I am a composition born out of a masterpiece. With me, the heritage of my parents can go no further because I am not Deaf.
The acronym is just a neat part of it, but in no way encapsulates the meaning of the term. The acronym, without the understanding of the reason the word was chosen, cheapens its meaning and does little to uplift the parents or the children. Not understanding the origins of the word leads to other acronyms that, without knowledge of coda rather than C.O.D.A. takes away from the Deaf community that brings about the coda.
The above was posted in the etymology section by User:Bruffman, but was moved here as it is unacceptable as a part of the entry unless rewritten in a more succinct, attestable way. --Tohru 15:52, 5 September 2009 (UTC)