My Dad stuttered as a kid but overcame it and won many speech debates. He was also an ultimately better man than Joek.
And let us not forget the late and great Mel Tillis.
I remember my dad working with my brother, on my brothers stutter. My brother overcame it in just a few weeks.
I think the stutter comes from thinking ahead, nervous, doubt, too fast. The mind is in a race, gets way past the words and doubles back. A train wreck. My dad had him practice, slowing down, relaxing, and pausing. The stutter was gone in a week and never came back.
I guess he was just lucky, the right cure for him came so early.