Your preteen probably thinks it's cool to use profanity, and if he's only speaking this way with his friends, and not in public, you don't need to be so concerned. Allow him the freedom to talk to his buddies in private. If the bad language does spill over into other conversations, you should firmly let your son know that this kind of language is not acceptable in certain circumstances, and that you'll deprive him of certain privileges if he disobeys. Sometimes if their peers are saying these words, they do it to be part of the group. Talk to him about being a leader and not a follower and how respect for himself will go a long way.
Words are relative and can be used to hurt or encourage.
I don't worry about particular words unless they are used to hurt others. Your problem is how to convince your child to stop talking long enough to do this. A middle school teacher from Yonkers, New York, explains that she deals with this problem in her classroom 90 percent of the time, so be reassured that your child is not unusual. She is probably just acting her age and struggling with her maturity level, and this is going to affect her relationship with her parents and teachers. This way they do not know that they are being singled out for their behavior.