I think everyone, to some extent, has a internal monolouge when they read. The solution isn't to turn it off, but training it to go faster.

Small hack to do this: I've found that listening to an audiobook at 2x up to 5x speed while following along on the page has increased the speed of reading while maintaining my comprehension.

Also when you read more books of the same kind, and get accustomed to the same kind of sentences, you'll naturally find it easier to read the words without the "voice". Your brain will start seeing words as sentences, sentences as paragraphs, and paragraphs as ideas. This is a slow process, and can take a while. But after a while, it's super cool to find your eyes speeding along a page, with your brain comprehending the sentences, without you even noticing.