This reminded me of a sort of similar topic, and curiously enough it's about reading, and might provide some insight into your question.
Some years ago, I happened on a thread in which the OP asked people whose voice they "heard" when they read.
I couldn't even make sense of that question. The only time I "hear" voices when I read is when a character speaks. The rest of the time, I not only don't "hear" the words - I'm not even really aware of them. My eyes follow the lines while my brain instantly translates the words I'm seeing into images and concepts and the like. And yes - it's like a movie playing out inside my brain, and yes, I'm a #1 on this chart.
But apparently there's a not insignificant number of people who "hear" a book inside their heads just as if someone else was reading it out loud. Instead of visualizing things, they remain focused only on the words - the representations - and somehow glean from them alone the necessary details.
I wouldn't be surprised if those people are also generally #5 or thereabouts on this chart, and again what it is is that their brains don't directly envision things but instead rely on descriptive representations.
I don't get how it works either, but self-evidently it does.
