What 'bad' language is appropriate for kids at what ages? For example, are words like sucked and crap OK for middle grade books? I mean, I think the kids use these words, but does that mean it's OK to put them in print for that age group? Will parents not buy books because of this? Some of the YA stuff I've seen is downright raunchy when it comes to language, and it surprises me that parents buy it for their kids.
This all depends more on your press’s tolerance for bad language than on the market’s. On the whole, traditional bad language is really just lazy language. They’re the words we use when we can’t be bothered to think up a more descriptive way to put things. For instance, when I drop a box of books on my foot, the word that comes to mind is “shit” because the pain in my foot momentarily distracts me from higher verbal abilities. So, to apply this to world of fiction, characters might use curses in dialogue but everything of a more expository nature should limit the use of bad language in favor of more descriptive (and interesting) figurative language.
As to the difference in midgrade and YA cursing, a lot of that has to do with the difference in intended markets. Older readers are supposed to be able to handle more complex issues. I’m not sure why, but cursing is considered a complex issue. In my opinion there’s very little complex about it. They’re simply words polite society does not like. Since polite society does not like to see a nine-year- old curse, those words are not in their books. As a society, we don’t care much if a teenager curses, so we allow those words in books for the YA market.
My take on the whole subject, is like sex, violence, rock ‘n roll, etc, the cursing had better be germane to the story. Just adding curses so that your YA seems “edgy” doesn’t cut it for me. The cursing needs to be natural to the story and a natural extension of what you are trying to get across. Don’t just curse for the hell of it. (Ah, that was fun.)