stammering causes to be evaluated clinically Reason: probably there may be a tongue tie (medical terminology)were the tongue is not freely moving to its full threshold and it happens to effect in phonation and patient stammers. Solution: you need to visit your dentist to get clinically checked and if that is then he would suggest for small procedure and that would make it restore back  to your normal fluency of speech and suggesting some exercises  for tongue . if not then you need to visit a speech therapist who are well trained to help people who stammer