https://www.youtube.com/watch?v=g3vSYbT1Aco&ab_channel=TED

Learned a lot from this video. You heard all kinds of voice from several level of masks, and your inward voice through your bones, not air. But magically there is the inner voice, maybe you can't really hear your own voice because your brain filters it. And you can hear your silence thought when you are reading.