Once you know something, it becomes almost impossible to really comprehend that other people DON'T know it.You can know that they don't, believe that they don't, act as though they don't, even, with effort, imagine what it must be like to experience that not-knowing. But with few exceptions, you can't really internalize. What is seen cannot be un-seen.
I think this is a big deal with vocabulary. Because words are such a fundamental part of the way we interact with the world, it's hard to imagine that people don't know the words that you know -- and more importantly, that people can't easily be made to understand the full depth of context that comes with a word.
I have this problem in a lot of conversations -- like, I know that people don't really know what I mean when I say post-modern or deconstruction. But I find myself regularly, repeatedly making the mistake of believing that all I have to do is explain, briefly, and then the conversation can continue from there.
Even though I spent years in school learning about what those words mean. Even though I know that, in my mind, an explanation of those words entails an explanation of the life stories of several philosophers, a handful of well-known anecdotes and media sources, as well as the associated commentary, and a reasonably solid footing in modernism.
I feel bad about that sometimes.