It's a chicken-egg scenario. Stuttering is not caused by not speaking enough. I know full well what my capabilities are and what is or isn't causing them, so I don't need evangelising. I agree to a point that being an effective speaker takes practice, but there's a world of difference between giving after-dinner speeches and talking to someone in a shop. Define 'unrelated to'? Not everybody puts the world to rights with random people on the street.