I have gradually improved my fluency in the past 30 years, but it still flares up by situation and mood. 10 years ago I had particularly great fluency after taking a 1-month seminar that was a good placebo to trick myself into being super confident. Much of this is known, but still requires constant focus. Everything he said about speech therapy is wrong for at least the past 30 years. I hate how people like him talk with such authority AND have to bring others down (falsely) to boost themselves up. His advice have elements that can work, but as an adult, those tactics won’t have the same effect.