I think there’s another aspect that people haven’t really pointed out yet: that most speakers and microphones are trash. With cameras and screens, we’ve gotten really good at capturing real life in pictures and then displaying those pictures. But microphones and speakers are fundamentally limited by physics. And most microphones and speakers that everyday people would have access to are limited by physics to be awful at picking up sounds accurately.

Try listening to the same song on a desktop speaker vs. earphones. Earphones just simply don’t reproduce the song to the same quality as the desktop speakers. They are terrible at reproducing low tones, and the balance is usually wack. Or, for instance, try talking to a friend via a Zoom call vs. talking in person. You can pretty easily tell the difference. You can get expensive equipment to capture and reproduce sounds more accurately, which is what streamers and youtubers tend to do, but then that’s very expensive and not really something that ordinary people would be willing to invest in.

That’s not to say that the other responses are wrong and that the resonance of the jawbone doesn’t affect how we perceive our own voices (they’re correct, and the resonance does affect our own perception), but simply saying that it’s just the resonance is missing out on the crucial detail that our voice recordings are fundamentally trash to begin with.

As an analogy, you can try taking a selfie using an old laptop’s front-facing camera. You probably won’t like how you look either - you’d look either sickly pale or drunken red, eyebags appear out of nowhere, the distortion of the lens makes you look fat. All of these qualities aren’t because you are any of these things in real life. It’s simply that laptop cameras are bad. Same is true for microphones and speakers.