Mouseferatu
Hero
Felon said:It's quite obvius that when you're reading dialogue that takes place in a place that's on another plane of existence altogether that you're reading a translation, not a transcript.
Bingo.

That is exactly how I see it, both in fantasy literature and RPGs. Once you've accepted the fact that what you're reading is an English "translation," then everything but truly modern slang becomes not only acceptable, but--one could argue--more realistic than deliberate attempts to sound "old-fashioned."
This is also, BTW, why I have no objection to puns and word puzzles in fantasy and RPGs. Okay, so maybe in the Common tongue of Greyhawk, or the language of Steven Brust's Dragaeran Empire, "live" isn't an anagram for "evil," and "right" doesn't mean both "correct" and "the opposite of left." But those languages no doubt have their own homonyms and synonyms for use in such puzzles. So I simply assume that the puzzle that makes sense in English is standing in for one that makes sense in Common (or whatever), and move on. There has to be an element of suspension of disbelief for any fiction that takes place in an alien environment, and this sort of thing, IMO--in terms of puns, word games, and profanity/swearing/reasonable amounts of slang--falls squarely into that category.