I never did speech therapy as a kid, and it wasn't very affective as an adult but I'd say the best thing I gained is acceptance of myself as a stutterer and a few lessons in anxiety reduction. I'm not saying there shouldn't be a focus on fluency techniques like soft starts and things like that. But learning how to control my anxiety level and just be OK with who I am has helped my fluency more then any vocalising skills have. Maybe some lessons on anxiety and mental health would be beneficial.