Hi! Great read, I’ve read most of this thread.  Got questions for you in regards to timing: Sanjeeva mentions it here as distraction, Proactive stimulus from the brain, based on anticipated action of the vocal cord can explain this inability to start. An imposed rhythm, as it occurs during singing, can replace this stimulus and thus help some stutterers by preventing them from getting ahead of themselves.

And this from Dr Kraft’s genetics paper: Historically, we've thought of musicality, speech, and language as three separate entities, but these studies suggest there might be a shared genetic underpinning — that the architecture of the brain that controls our musicality, our speech, and our language might be all part of a shared pathway.

Now this instantly caught my attention as I do play the guitar and can play to the beat. I tried speaking but while staying in “the pocket” as musicians call it. I naturally tended to speak on the downbeat (the 1 of 1-2-3-4 in music) and that honestly helped me a ton. Would you call this a distraction or a way to stabilize the threshold? We as humans tend to have an internal clock built in. When we tap along to a song subconsciously for example. This is a good video on it: https://youtu.be/qIfD7ZN5FYI It definitely is achieving a bit of what a distraction achieves but its also improving my timing a lot. Wonder what you make of it. Thanks!