i'm much like this, but i don't recall explicitly teaching myself to hear words in my head, and references to people moving their lips while reading (or talking out loud to themselves) confused me for the longest time.

i've learned from doing recent reading aloud on car trips that i do not, in fact, pay the same sort of attention to the sound of writing when i'm reading it to myself as when i'm reading it aloud.

like some other commenters here, i absolutely notice misspellings and weird punctuation in writing, but that still feels like a visual thing-- a misspelled word looks wrong to me.

i don't see letters when people talk unless they emphasize initial capitals or something.