Actually, technically I might have mouthworms. Until I read one of Oliver Sacks' popular books about neurology, I didn’t realize that when people say they hear music in their head they mean they actually hear it.

I’m one of those rare (but not astonishingly rare) people who don’t. I hum a lot, though, and sort of sing to myself under my breath, because that is the only way I can hear music I’m not actively listening to.

None of my dreams ever contain sound either.

Weird but true!