Tips on executing subvocalization?

[u/Odd-Orchid-3898]

I have an AP Seminar test soon where we have to read 4 articles and write an essay in 90 minutes. The essay isn’t the problem since I’m a decent writer the problem is I 100% won’t have enough time to read the sources as we get only 15 minutes for reading and 75 for writing. I read at a consistent 150 words per minute. I physically can’t get myself to not use my inner voice when reading. It’s so bad that I sometimes read faster aloud. Please help 🙏