I hope it's ok to share this, but it doesn't feel right not to respond to your post here. I'm a professional singer and actor and private voice teacher. I spoke with a prominent stutter into my early 30s and although it still comes out here and there from time to time (I'm in my late 50s now), there were a few things over the years in my professional training that really helped me so so much, that I created a retreat workshop out of them for anyone, speech impeded or not, (and whether or not they can sing) who is interested in exploring their relationship with their voice. It's called Exploring Communication through Song, Breath, Voice, and Mindset. It incorporates Meisner based acting exercises, breath and voice exercises to help develop a more stable scaffolding in the body for the voice to lean into, inspiration from Kristin Linklater's book Freeing Shakespeare's Voice, and Anthony Braxton's Syntactical Ghost Trance Music. You can probably find it if you Google the title, or you can message me here if you'd like to know more.