I had a 6% percent disfluency that was still ranked severe, because instead of a stammer or little catch in my voice it was a full on indefinite stutter that I couldn't recover from. Speech therapy did jack shit for me. Mostly because I had a therapist like the one mentioned in the other comment. She would ask me to rank my anxiety level every session, and then want to talk about my life like some therapist. We never actually got to methods to reduce my stutter in the 16 weeks I saw her. That being said OP, your experience may totally vary from mine!