Don't play his game. Don't struggle. Ignore him. Leave the room. Read a book. He will get tired of talking to empty air.
As for his bad mouthing you, when one of my kiddies tried that I slapped her in the mouth. She never did it again. P.S. I was not a slapper, but some things are best nipped in the bud. Each of my four kids got only one or two slaps in their lives. Maybe that is why they were so effective.
I actually think this is pretty normal stuff. It's not appropriate behavior, but it's not overly uncommon. One of the things I would do is talk to his teachers as to how they handle it when he does it in school. I know my 3 year old's school doesn't discipline at all. However, how I handle negative behavior at home does carry over to his behavior in school. So I would ask you, is he kicking and hurting at home?
When he kicks or hits, don't warn him. Stay calm, pick him up and tell him that unfortunately he needs quiet time in his room. Don't show you are upset, don't yell (this always just makes things worse I think). Just tell him that he has to go to his room, and take him there. Close the door. Don't go back in until he has calmed down (he will probably scream). When he's done, open the door, and in a cheery voice, just tell him "Oh good, your all done. Now we can play". Give him a hug, and it's all done. Be consistent - this needs to happen every single time.
Also, watch your own behaviors at home. If you or his father are yellers, he is going to copy that behavior. I'm not saying you are, just that it's important to remember they are watching, listening and learning. Once he learns he isn't going to get away with it at home, I bet the issue starts to resolve at school as well. Good luck. This has worked well for us with tantrums and things like hitting. Oh, and when he does co operate or do as he is asked, make a big deal about it. Kids this age do love to please, so telling them how happy their actions or behavior made mommy and daddy, and how proud you are goes an amazingly long way. At least it does for us.
Could he have learned this behavior from some one else, has he siblings baby sitters etc does anyone else you know behave the same or similar?
Hi Van, i would take him for some counseling. Doctors can help with with the anger management and the earlier you start this the more it will help. These are habits he has developed. Some times children pick these habits up from other family members as it works for them.