>>24556983
it can be either of those two things.
I think most people slightly imagine how the words sound inside their head.

If you want to read fast you need to silence the subvocalization as much as possible. That way you can better comprehend more words at once and faster, because you're not restrained by the time it takes to 'say' them in your head. for example, you can take larger snapshots of the text while still getting the meaning of it, without loosing comprehension, even increasing comprehension.
You can practice this by looking at the space between words, that way you read the two words beside the space at once. Then when you get good at that, you can increase it to 3 words. then more, and faster. You just need to challenge yourself a little bit, so you read at the speed of the edge of your comprehension. each time you move your eye, you stay there until you have comprehended what's written, then you move your eyes to the next spot, but you push it to the limit. If you practice with this basic speedreading technique you can get to read extremely fast with full comprehension.
There are other more advanced techniques, but you can get very far, very fast with this one.