I am an ex stutterer. Following a car accident, wherein I received a TBI, I also eventually found that I no longer stutter The best explanation I can come up with is as follows: I used to subconsciously suck in my gut , which involved engaging my abdominal muscles and contorting my midriff. This had the effect of impeding my diaphragm from trying to push my breath out through my vocal cords. That's what I think anyway. Check this out:https://youtu.be/bkY9C7VX8ww