My parents noticed this and gave me a speed reading book. I incorporated each an every item on that book including the removal of subvocalization. It certainly gave returns right away, allowing me to consume books at a faster rate, but a huge cost.
Years later, I entered college as an engineering student. I noticed that when reading highly technical textbooks, and classes that required deep comprehension of text, I was much much slower that my classmates, or my comprehension level was much lower. Turns out, it was taking almost double the time for me to get through a section.
Really wished I didnt read the speed reading book now. I dont blame my parents at all, it was unfortunate that at nearly 40, i'm still trying to unlearn what that speed reading book taught me. I'm trying to re-learn subvocalication but its very very hard to 'slow' myself down. I've actually installed screen readers to replace subvocalization with some positive effect.