Mostly I'm talking about werewolf fics, but this applies to anything similar, where the characters get some sort of instincts relating to interpersonal relationships/society.
Have you noticed that, 99.9% of the time, they immediately start using the vocabulary of their new society--like in werewolf fic, they immediately call themselves a pack and the leader the Alpha. It's one thing if the characters are previously aware of this hierarchy or are given an introduction to the way things are run by somebody who previously knows/uses the vocabulary, but it's a completely different thing if they immediately, without any thought on the matter, start using the terminology without that introduction. I mean, yeah, if I got bit by a wolf and started having instinctual reactions to people, it wouldn't take me long to start calling people alphas and pack simply because that's the terminology I know, but it would still take me a while before I started to use them. Maybe just a few seconds, if it was fairly obvious what had happened, but I'd still start out fumbling for words to describe what my instincts were telling me. And I'm not unique--anybody would react the same way in that situation.
And, again, you have to consider the situation; if you want to skip the whole "learning about being a werewolf" stage (which could be good for a outsider "wow, you've changed completely and yet you don't seem to be freaking out at all" reaction), you can make it so that the instincts tell them everything they need to know, including the terminology. But be smart about it. If they're stumbling around in the dark, they're not going to automatically know the terminology.