Maybe we use our brain in one way when we are alone and in another way when we are together with others. Maybe it’s anxiety maybe it’s just malfunction . To me the biggest mystery is; why can’t “science” just figure it out and cure it? The anxiety part is interesting. It’s also very hard to come to grips with. Many stuttering therapies seams to reduce anxiety and make people more okey with stuttering and so on. So maybe reduced anxiety leads to less stuttering or maybe just make you more okey with it. But you will feel better anyway. Also some people that play roles in theatre don’t stutter , but they most have a lot of anxiety but maybe they can manage it.