I hit my head while trying to do a flip into a pool when I was young. I know that sounds bad but it happened in a way where my momentum on the side of the pool wasn’t too bad and I still landed in the pool, it’s just that my head hit the side for a second. Thankfully it really wasn’t too bad: No serious brain damage or anything like that but it did hurt like hell for the first 10 minutes. Now I can’t remember if I stuttered before that or not. Even if it was what caused it I’m not upset about it. Probably shouldn’t have tried doing a flip at a young age with no practice.