Practice full breaths with the diaphragm, not the chest. Relax your jaw and articulators during the inhalation. Inhale at a relaxed pace. At the top of the breath, relax your diaphragm and let the air out; don’t push it out during the exhalation. Don’t take in TOO much air, or you’ll feel your vocal folds constrict at the top of the breath; this tension will contribute to blocks. When you feel comfortable with this sort of breathing, start incorporating speech (I recommend practicing alone): inhale as described above, then immediately start speaking when you exhale. Don’t pause at the top of the breath or your vocal folds will constrict. Try to make the first sound of each syllable as gently as you can; for example, if saying “poop,” make the p’s very light but say the “oo” at normal volume. See if these gentle consonants help get the vowels out. It’s good to also be gentle with the final sound of each syllable, as this will help set up the next one. I’d recommend practicing this for 20 minutes a day at least. When you start using these techniques in the real world, you’ll find it much more difficult at first. Be patient with yourself. If you get stuck, don’t try to force it out; let the air out and try again. If you try to force sounds out you will reinforce bad habits. The more consistent you are, the easier it’ll get. I hope you find this helpful.