My son would say in appropriate things and one of the things I did was take myself away. It drove him nuts. If he was saying mean or disrepectful things in the car, I told him that he was not being nice and until he could be, I was through speaking to him. At home, I would walk away and tell him that I could not be around him until he was nice because I did not want to "hang around" a rude person. Most of the time it worked as he really wanted to be around me and my not talking to him was probably the worst punishment for him at that age. Now, he is a few years older and I just tell him his behavoir is not okay to go to his room until he is ready to be a polite person. As he is not so attached to me at this age, it works better because he keeps very few toys there and really wants to be out in the living room where the people are. He also must apologize for the the inappropriate behavoir before I would speak to him or before he can come out and join us in the living room. When he would hit at school, I used pretty much the same idea. I told him hitting was not appropriate and would not be tolerated. He was put in time out if he hit. If he threatened it in the car, I again would tell him that was not okay to say or do and I wanted nothing to do with him while he had that behavoir. Good luck.