“You shall not insult the deaf” is in the third book of the Torah and third book of the Old Testament – otherwise known as Leviticus.
Just don’t do it… it’s not permissible by God. I don’t want to hear any more about some guy banging a deaf person on the head because the deaf person didn’t hear him. I don’t want to hear any more about the deaf person who gets denied a job even though he’s the most qualified individual for it, simply because he’s deaf. Please and thank you.
This article brought up one of many perspectives on Cochlear Implants – how some deaf people feel like there is nothing that is “broken” and thus no reason for something to be fixed. It also argues the other side – i.e. why it would be permissible. Keep in mind that it’s in accordance with Jewish learnings.