I can relate to your experience, talking about how its linked to your mental health feels super close to my understanding of my stammer. I spent a great deal of my childhood and early 20s, just not really talking that much. I think that is the easiest form of avoidance we have, right? I have never tried the technique you mentioned, but I like the idea of being still and quiet for an extended period of time. Have you looked into meditation? To be quiet in both the mouth and mind could lead to some nice realisations.