I have aphantasia. When reading I also don't "hear" the words (although I am capable, if I choose, of mentally simulating auditory input in a way for which I have no corresponding capability for visual input). I think I read much faster than average and have extremely high reading comprehension and recall for written material.
Funny story: one benefit of not being able to visualize things is that I'm never disappointed by casting choices (at least as far as appearance is concerned) when a novel is made into a movie or TV series. My wife was "upset" that Jaime Lannister in the Game of Thrones show had blue eyes instead of green, because she had such a strong visual image of what he should look like.
Your description of being capable of simulating "hearing the words" resonates with me.
When I think about it more, I think I almost feel the sounds on my tongue, which is to say, when I try to simulate the sounds, I do so by imagining how I would make the sounds with my mouth.
Also your point about casting choices for movie adaptations resonates. When a movie is made of a book I've been reading I'm almost always just so pleased by finally being able to see what the character looks like, and have never felt disappointment.
If anything while reading about characters, my mind cycles over possible physical attributes wondering which a character might have, but never really building anything resembling imagery.
Funny story: one benefit of not being able to visualize things is that I'm never disappointed by casting choices (at least as far as appearance is concerned) when a novel is made into a movie or TV series. My wife was "upset" that Jaime Lannister in the Game of Thrones show had blue eyes instead of green, because she had such a strong visual image of what he should look like.