In my opinion speech therapy does work by teaching you how to have less stuttering/stammering but in my opinion it just replaces one problem with another where you end up talking in a very slow, monotone that often sounds very scripted and expressionless. Perhaps I needed a better speech therapist but that was my experience after a year of speech therapy. I would also rate my stuttering as a 7-8/10 so on the more severe end where I have a repetition or blockage every 2-3 sentences.