I have, on more than one occasion, seen this fantasy author or that criticized for word choice. Not that they picked the wrong word for their intended meaning, but they picked a word that didn't "feel" fantasy enough. It shattered a given reader's suspension of disbelief; it broke the fourth wall, and tore them out of the novel.
I have been accused of such myself, in fact.
And I'm not suggesting that such complaints are automatically invalid. It's absolutely possible for a fantasy author to go too far. Particularly modern slang, for instance, sounds woefully out of place in a fantasy setting. I don't ever want to see a knight in a medieval-style Feudal society utter the phrase "That was the bomb, yo!" or hear an elf refer to the actions of his rival as "Whack."
(Well, I usually don't. Now I suddenly have a perverse urge to read, or even write, a short story in which everyone talks like that. But that's beside the point.)
But the criticism I'm speaking of doesn't extend to examples that egregious. They are complaints such as "You should never have puns in fantasy, because the characters aren't really speaking English, so the puns wouldn't actually work in whatever language they are speaking." Or things like "Timothy Zahn shouldn't have used the word 'katana' in his Star Wars trilogy." Or, to bring the example closer to home, a reviewer who said I shouldn't have used the word "origami" in Agents of Artifice. (Just to be clear, I don't want anyone to get the impression I'm calling the guy out. I'm not; it's just a convenient example. Heck, the overall review was quite positive.)
And while I understand these arguments, I utterly--even vehemently--disagree with them.
Let's take the latter two complaints first. Why shouldn't those terms be used? Because there's no Japan in the universes of Star Wars or Magic: the Gathering? Well, no. But there's also no England, yet we don't mind the fact that most of the terms come from English. Are we suggesting that in none of the Star Wars worlds has anyone ever developed a sword like the katana? And if they have, why is it any less appropriate to use that word for it than it is to use the word "sabre" or "sword" when describing lightsabres?
Magic: the Gathering does include at least one world that is very heavily based on feudal Japan. So there's zero reason to think the art of origami doesn't exist. Again, if it does, why should the author go about finding a brand new word for that art form--which he then needs to take time to explain to the reader--when a perfectly good word exists and already has an accepted meaning (albeit a borrowed one) in English?
It's inefficient. It wastes word count and the reader's time. Now, if there was truly a major flavor difference--if the word in question was something incredibly modern, with major pop culture connotations--that might be worth it. But most of the time, it just isn't. Especially since, even if the author does provide the new meaning to the reader, it still may not have the same impact or recognition as a word they already know.
What about puns and wordplay, though? Okay, that argument holds a little more merit. To use an old, traditional example, there's no reason that the words for "threw" and "through" sound alike in the language of some fantasy culture, even though they do in English. Therefore, characters shouldn't be making puns that rely on that sound, right?
Well, no. It's true that the communal illusion of fantasy, accepted by readers and writers both, is that the characters usually aren't really speaking English, so (in a sense) the author is "translating" the character's dialogue into a language the reader can understand. It's not something most of us think about actively or consciously, but it's the only way the whole setup actually works.
But as any translator will tell you, translating dialogue or fiction from one language to another isn't just about swapping out words. You have to rewrite things. Phrases that flow in one language don't in another. Slang and metaphor don't carry across. Humor doesn't always translate. The act of translation is one of conveying intended meaning and feel, not just precise word choice.
So yes, "threw" and "through" may not sound at all alike in the language of, say, the wood elves of Hippie-Grove Forest. On the other hand, perhaps in their language, the words for "thumb" and "xylophone" do sound the same. Thing is, there's no way to convey that particular pun to English speakers.
My assumption, then--on the rare occasions that I'm bothering to think of it at all--is that, if I come across a pun that wouldn't work in the fantasy language in question, I assume it's a stand in for a pun that would have worked, but wouldn't in our own language.
It may feel a bit convoluted to some of you, and I certainly understand that. But I think it's a necessary leap to maintain the shared fiction. Either we can use the language we're writing in, and justify it, or we can't--and we strip authors of a huge portion of their toolbox, and make their books less flexible, less enjoyable.
Of course, everyone's going to draw their lines in different places. For some, it's the use of words that come from common names. In The Goblin Corps, I used the word "non-euclidean" at one point. I know some people object to it, and I absolutely understand why. I questioned its use myself. After all, there probably wasn't a Euclid in the history of that world. But ultimately, I decided that it was the only efficient way to get that point across, and that I'd just have to assume (if asked) that the name was a "translation" of whatever mathematician invented the concept in that setting. A number of readers won't agree with that choice, but it remains a deliberate one.
(This is also, BTW, why I don't really care for made-up curse words. When it's on TV, or some other medium where you aren't allowed to curse, I can deal with the occasional "frak." But otherwise? Say what you mean, damn it!)
Ultimately, there are always going to be some word choices that pull you, me, or any given reader out of the text. That's just the nature of the beast. Next time it happens, though, give at least a brief bit of thought as to why the author might have chosen that word--and how much it would actually have added, if anything, for him to go back through and have to invent, and then explain, a replacement. I think you'll find that, the vast majority of the time, it wouldn't have been an improvement at all.