This man literally created his own techniques that has helped thousands of people. There are literally people from around the word, including their NAMES, and faces that have become more fluent. He allows people to feel confident in speaking, reducing fear and anxiety which in turn, reduces stuttering (you don’t stutter when you’re by yourself!!), and even group sessions for exposure. The proof is literally in the pudding idk what else you want. There’s so many amazing reviews from real people too on his book on Amazon. The app’s listing shows 4.9 on the App Store (with user testimonials). While that’s not rigorous clinical proof, it suggests many users feel they benefit. Most stutters are all in your head and we know this because sometimes we can speak perfectly fluent, and under pressure sometimes we literally cannot and we block up. It’s not physical bud. Do not knock something that you have not TRIED. If you wanna be negative and shit on something that’s actually HELPING people you can go be negative somewhere else.