I think the trick is really to remind readers from time to time, rather then every other word.
Being from Canada, I know many people who have gotten upset regarding TV shows that over use the word Eh. Even if it's truth with some of the people I know, over using that word at the end of every sentence, I've decoverd that people are more content with first knowing where the person is from and then secondly getting the off and on reminder of that note.
Ie. Dude, although is starting to become a trend it still commonly thought of a slang used for sufers. If the writer first explains were the character is from ie LA who has this great tan becuase he was sufering all the time there. Then used the word Dude everyone once in a while to remind us, 'oh yeah he's from LA.' That what I find words best.
I think a few other fans of yours have already stated something along these lines I just didn't want to feel left out.
Later