Like how did mine go away? As a kid, I simply outgrew it. I guess my brain adapted to whatever issue there was at least as much as it needed to for me to speak fluently. As far as it “going away” after the clinic? It wasn’t as much gone as it was under control by me. The clinic was 10 hours a day of group speech therapy for 10 days in a row, and so I’d gained so much confidence in my ability to use these techniques whenever I wanted, in whatever situation I was in (we did a lot of group work, public speaking, outings, etc.), that the mental component basically got extinguished.