When I get drunk, I use longer and more precise words. This is because I speak that way naturally, or, at least, I used to. Then I started having to interact with mundanes, and started using shorter and more common words. There's an inhibition in place against my using the more esoteric words in my lexicon under normal circumstances. But when I get drunk, I am stripped of the restraint and there I go.
When I was on the bus in high school, the Nash brothers commented that they could tell when I became angry, because they stopped being able to understand me. They could hear the words just fine -- they just didn't know what half of them meant.
I should take up reading the dictionary again. I don't want to actually lose my vocabulary.