I do want to point out one thing about "the more education a person has, the larger and more polysyllabic their vocabulary." This is true to some point, but it's often not noticeable. I know people with PhD.s who know more jargon, but their conversation isn't markedly different from people who only have a bachelor's. (I mention this because I'm really tired of seeing people denote geniuses in stories by giving them large vocabularies and then smirk because the psychology PhD. doesn't memorize the dictionary for fun.) One of my high school teachers used to say that in essays, impress him with big ideas, not big words, and I still use that measure today. The smartest people I know have ideas about things or can discuss ideas intelligently; they often do not demonstrate a vocabulary larger than mine (and when they do, it's often a social class thing - I'd never heard of 'charcuterie,' but my upper-middle/upper class roommate acted like it was an everyday word).
I don't know a lot of people who only have high school degrees, so I can't talk about their vocabularies.