Why do i stutter sometimes, and how can i stop it from happening?

It's complicated: See a good speech therapist who has worked with others. Go watch "the king's speech" dvd and watch the special features. Churchill also stuttered and helped himself. It is often worse with nerves and anxiety, and interestingly many stutterers don't do it when they sing. It takes focus, determination, time and guidance, and working with somebody with experience in helping others with same problem.

Consult: Have a consultation with a speech and language therapist of evaluation and treatment.