Aspects of this topic are discussed in the following places at Britannica.
...physiological activity. In the hyperkinetic disorders, the highly coordinated patterns of phonation regress to the primitive, forceful, and exaggerated sphincter action of the larynx as seen during gagging. The result is hyperkinetic dysphonia, the gratingly harsh vocal disorder due to excessive muscular action in a constricted larynx. In the second subtype, the movements for phonation regress...
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