Why is that?

There’s an easy explanation for experiences like Ms. Miyawaki’s, said William Hartmann, a physics professor at Michigan State University who specializes in acoustics and psychoacoustics.

There are two pathways through which we perceive our own voice when we speak, he explained. One is the route through which we perceive most other sounds. Waves travel from the air through the chain of our hearing systems, traversing the outer, middle and inner ear.

But because our vocal cords vibrate when we speak, a second path is introduced internally, in which those vibrations are conducted through our bones and excite our inner ears directly.

“The effect of this is to emphasize lower frequencies, and that makes the voice sound deeper and richer to yourself,” Professor Hartmann said.

Except when it doesn’t: Professor Hartmann’s explanation makes sense for many people, including Ms. Miyawaki. But it does not quite work for my classmate Walter or for me.

John J. Rosowski, a professor and researcher at Harvard Medical School who specializes in the middle ear, filled in the gap. He said that there might be variation in our perception given that, within the two pathways Professor Hartmann outlined, there were more nuanced ways for sounds to be perceived by the inner ear.

“There are multiple paths that these vibrations take to get to the skull,” Dr. Rosowski said. “They include the vibrations of the skull itself, which can vary.”