Yes, this is quite an obscure poem. There is very little written about it, and even the poem itself is hard to find. Nonetheless, the poem's meaning in rather accessible. It is about what the title suggests: stutterering and the problems associated with trying to get muscles and breathing to work seamlessly for fluent speech.
I have known people who struggled with the problem of stuttering. This poem explores the condition in harrowing, even violent detail. It describes the extreme difficulty the stutterer has controlling his or her tongue, and mouth and breath. Activities we natural speakers take for granted are torture for the stutterer. For not only can they not form words at all at times, they are deeply frustrated because they are blocked by the inability to communicate, unable to share their ideas. It is both physical and mental frustration in the extreme.
The suggestion given near the end of the poem is advice I was told worked for a stutterer I knew: learn to relax. Take lessons in relaxation. Bio-feedback and yoga have been known to help. Stutterers are so vexed by their inability to get words out that they work themselves up to a nervous state that makes the stuttering worse. If they can let go of the frustration and struggle and clear their minds, the problem can become less and less severe.