I grew up with an absolutely horrible, debilitating stutter, and it was what caused me to retreat into myself and caused me to have very few friends and not want to socialize, and it made me absolutely terrified of giving reports in school. It was awful. It wasn't until I was 19 that I had intensive speech therapy. I had it for two years and it really helped, though I will say when I'm tired, the stutter comes out, even now.