its all psychological, I had a stutter that developed because of stress in school, and I thought of myself less. and y'know put myself down. Then I re-affirmed I had a stutter and told myself I do, and it made it worse to the point I was afraid of speaking. 2 Years clean of stuttering, by just realising its all in my head, and that if i let go of the belief I have one, then it will let go off me too. And I now give speeches fluently.