That's the thing. If you are reading a document and/or literature or any form of writing really and you don't understand the words; you're reading above your level, a need to start with more simplified material is most likely required. Reading is one of the only ways to improve this, think like experience at a job or with a hobby. You only improve by doing it. Even encyclopedias are interesting if you get your hands on older ones that are not completely kiked out. For example mine are hand me downs from my grandparents and from the 70s, my Websters dictionary as well and my thesaurus is from 1990. I find physical books are the best way to absorb yourself into the writing and not be distracted by pop-ups, digital commercials or bright screens burning out your eyes over hours of reading. Audio books are okay depending on who is narrating it. I don't want to hear a fag accent, a nigger, a jew or a spic talking. I just want to hear a White person using proper English. Also, always have a thesaurus or dictionary on hand if you're absorbing new information in a learning standpoint.