One of the papers I need to complete over Christmas break is an address I'm going to be giving in January at Pusan University of Foreign Studies (in Korea) tentatively entitled "Historical Linguistics and TESOL." [Yes, I know the title is dull. I'll punch it up if I have time]. The audience will be graduate students in a TESOL program.
I always forget how much harder it is to write for non-native speakers of English. When I'm writing for Korean medievalists, I can be more free-wheeling, since you don't become a professor of medieval or early modern English unless you are already pretty proficient in modern English; I don't know of any other organization in Korea with English as good as MEMESAK (the Medieval and Early Modern English Studies Association of Korea), for example. The least of their members has English far superior to what my Korean could ever be.
Speaking to an audience of people not long past their BA's, though, is another proposition. Things to avoid: narrow cultural allusions, phrasal verbs, academic jargon, long clauses, etc. It makes writing a lot slower going -- I'm working at about one hour per page, when (in the right mood) I can usually double that rate for an English-speaking audience.
On the plus side: I get to talk about the Korean gangster movie Chingoo. Somehow I doubt I could make reference to that film to many other audiences.