I watched a movie by Harrison Ford and there are some lines,
H: I can't talk to you.
J: You can't talk? You won't talk? You don't want to talk?
H: I can't talk. I won't talk. I don't want to talk.
H was fired by a cigarette company and J was a journalist who wanted to ask for some dirty secretes about the company from H. This conversation was by tax.
I guess I know "can't talk" here means "I am not allowed to talk". I also think I know the difference between "you won't" and "you don't want". They both mean admonition. But I am not sure what is the difference between "I won't" and "I don't want".