They never helped me 100%. The only one that mostly helped was light steady breathing into the sounds that give you the most trouble. Like, breathe into the sound and give the sound air/breath like you’re giving gas to a car at a slow steady pace. It loosens up your muscles and helps you ease into the word. After awhile and enough focused practice it comes somewhat naturally. That and a lot of focus and meditation into your center self. I hope I explained this and made it clear. Edit: I’m not a speech therapist or a financial advisor. 💎🙌🏼