Why is using inappropriate language become the norm for some people. How can students learn to speak more appropriately. When is it necessary and when

I do believe that it is wrong to use inappropriate language around or toward others. I have tried hard to stop but sometimes people provoke me and I might slip a few bad words. I think its become the norm because we hear it at home from our parents and then we hear it from our peers at school. It has grown on me and I know I need to stop but sometimes I feel it necessary.....KLJ♥