I did speech therapy when I was 21. (I’m 55 now). Helped me tremendously! It was expensive tho and at the end, when I thought I was “cured” the therapist told me “no, you’ll always stutter, now you have tools”. Frustrating, but still glad I did it. The two tips I remember is to put an H in front of words that start with vowels (say hAPPLE instead of apple) and an A in front of consonants. :)