Are you sure you naturally talk fast or did it come due stuttering? Or did you start to talk faster because you felt the other person gets impatient and you try to safe time? Or you subconsciously try to get your words as fast out as possible? That's stuff you have to find out for yourself. If it's a coping mechanism, I'd say get rid of it and talk slow. With slow speech comes pretty much automatically more awareness on speech. Might be a sign, the universe telling yourself "slowdown you are to fast"