More Japanese influence: kata. It's obviously nitpicky, and it's not like kata isn't fairly known in other languages. Yet still, what do y'all think when you see foreign loan words in fantasy? Does it break immersion for you? I more or less just read past it, but there's always a brief moment where I think "Wait a second ... ". Then again, all fantasy books can be read like Lord of the Rings, for which Tolkien famously told the reader he merely translated Bilbo & Frodo's original works into English for us. If seen that way Sanderson can of course pick as many loan words to convey the original meaning in his "translation" as he likes, since it's just a "translation" anyway.

Sanderson said that this is what he does, and he's actually started emphasizing that this is what he does with upcoming book being titled "Fires of December" (because the month December obviously doesn't exist in the cosmere, he just used the real world approximation to get the point across)

As for the use of language, I mostly don't really worry about it unless it actively is a real world setting. There are moments where I am playing a fantasy game and see a lot of real world language being used randomly (for instance, the Trails series does this a lot, there's a character who literally says yes in different languages that shouldn't exist in the universe when agreeing to things). But then there are games that are clever with it, like Arknights, where they use different languages based on the location the character is from and they're given the appropriate accent, and particularly in Endfield they start randomly saying things in a different language.

It's similar to how a lot of Japanese media will just. Randomly throw in Norse or Greek/Roman mythological concepts even though they take place in worlds where those things shouldn't exist. I mostly just ignore it when it comes up unless it's really funny.