Mine definitely is. I had a severely traumatic childhood that I did my best to suppress the effects of for a long time. When I finally started to talk about it my stammer just appeared one day. The exact contours of it are very strange to me, and still something I'm learning about, but I stammer to the degree that I'm emotionally upset and connected internally to that feeling. I am usually able to stop my stammer by focusing on being emotionally disconnected. I try not to though because it is the voice of a badly abandoned and terrorised little boy, my voice, and it is time for it to be heard.