(I missed the beginning of the film, so do forgive me if I get the details wrong.)
In Sound and Fury, were introduced to a discourse that some are unware of its very existence: Deaf Culture. There are deaf schools, deaf communities, and deaf families and they take pride in their ability to live a fulfilling life with their handicap. But it is a handicap, and although it can be fixed, many of the people whose stories were told in this film felt it shouldn't be.
Were introduced to two families: one that is entirely deaf, and the other that is comprised of a deaf twin, but also hearing parents and a hearing twin. The parents of the hearing mother are deaf, and the parents of the deaf brother belonging to the deaf family and hearing brother belonging to the hearing family are hearing.
The deaf parents and grandparents have been deaf all of their lives and would likely never develop speech, but present technology has developed cochlear implants that could grant the ability to hear and speak to the deaf family's four-year-old daughter, and the hearing family's eleven-month-old son.
Surprisingly, there is uproar from the deaf side. Instead of being happy that the childrens' handicaps are more or less gone with the help of a cochlear implant, they are sad and scared that if people can be "cured" of deafness, deaf language, sign language, and even deaf people may go extinct all together.
The deaf people in the film believe that there is a deaf culture, and by a formerly deaf person suddenly being able to hear will remove them from the culture. This was difficult for me to understand personally, because surely you can still use sign language if you're able to hear, and thus be as much a part of deaf culture as you were before. Only know, you're multicultural; you are a part of the hearing culture that delights in music, the sounds of nature, and tones of voice, and you're part of the deaf culture in which body language and the other senses are likely much more important.
With criticism and arguments from both sides, the mostly-hearing family decides to go ahead with the cochlear implant and are delighted that their son can now hear. The deaf family decides to move to a more deaf-friendly community and not get a cochlear implant for their daughter. I personally believe the deaf parents are denying their daughter the best life she can have by not taking every action to make sure she doesn't suffer from a handicap. She can still communicate with them through the sign language she already knows and will likely continue to develop; they are denying her the opportunity to communicate with those who don't know sign language, and to pursue hobbies, friendships, and careers of which hearing is helpful or even required.
The hearing family seemed to make a much wiser choice in getting a cochlear implant for their son. Even if it was not his choice to have one, I am sure he will appreciate the fact that a hearing life is a much easier and possibly more fulfilling life. That's not to say deaf people don't lead fulfilling lives - I'm sure many do - but deafness is a handicap, and until we live in a world where every possible concession is made for those who are deaf, it makes life more difficult. However, not being a part of the Deaf Culture Discourse, I suppose it is impossible to truly know the full story and feelings of those who are a part of that specific discourse.