This is a statement of fact. It's how the body is constructed, the feeling of listening being a matter of vestibular function, which explains how a deaf singer like Mandy Harvey can sing. Yeah. Really. She can sing, and does so quite well, thank you very much.
Muscle memory? It is more than that. It's the ear and brain that does the singing. While Harvey's cochlea is fried, her vestibular function—the feeling of the voice—is intact and the principle means through which her voice is guided—vestibular function itself involving a great deal more than balancing the body in space.
How did Harvey get her voice working again after completely losing her hearing at the age of eighteen? She used a smartphone app to see what pitch she was singing, then felt her way forward. Simple really. So simple as to be disregarded by smartypants people everywhere. You know, of course, that the cranial nerves that regulate sight and hearing run along the same pathway, right? Those who know what they are doing can even look in a mirror and see what the ear is doing in relation to the voice. But what do most people do when they look in a mirror while they are singing? Become self-conscious rather than self-aware.
Great singing feels incredible. It's a rush, a wave, a cascade of endorphins that fills every nook and cranny of your cranium & body. This is why G. B Lamperti said that you could sing when you felt it in your fingers and toes. That's listening people. Inhale quietly for 18 seconds and you may begin to understand what this means.
Sounds still exist. You can feel music everywhere. — Mandy Harvey