To me, I find that I speed up my speech because I already don't take full breaths. Obviously stuttering is because of the brain not knowing how to breathe right for speech. Short breaths = stuttered/stammered speech. Short breaths also means faster speech because you have less air to get the amount of words out. In the future, try focusing on taking deeper breaths and letting it out slowly as you speak, and then of course slowing down your pronunciation.