This simple concept is what makes fantasy magical.
Something a lot of writers don’t understand when they starts writing fantasy that isn’t of this world (meaning no connection to Earth or real history) is that it’s technically in translation.
You’re fantasy protagonist doesn’t know English, or any other Earthly language. They speak a fictional language, but you, the author, have come along and “translated” their story into English.
Why is this important? Well it avoids a lot of problems, such as how we express time and space. Even on Earth we can’t seem to agree on things like distance. Some places use inches and others use centimeters. If you’ve taken any math class ever then you’ve probably had to covert (or translate) one to the other. As an author this is exactly what you’re doing with your fantasy novel.
There are unwritten rules to this however. Things typically kept the same as Earth are time and distance. Fantasy characters still say “Wait a minute,” and “I’ll be back in three days”, despite their calendars and clocks theoretically being different. Why? Because you’re translating their meaning into English.
Some authors want to make their world feel so authentic they try to make up words for everything from currency to gravity. Don’t get me wrong, world-building is one of the reasons I fell in love with the genre — but you can have too much of a good thing.
If you’re unsure whether to use a word or not, imagine the story your writing is in another language and you’re putting it into English. If your fantasy characters have a word in their language that means the exact same thing as the English word you’re using, then it’s fine and readers aren’t going to notice.
But you’ve got to watch out for anachronisms. Technically, anachronism only refers to things ‘out of time’ but I’ve often encountered people using it to mean ‘out of place’. For example, you can’t say “it was quite Freudian” in a fantasy novel because Freud was a real person from Earth. Fantasy characters can’t make that reference. Avoid any words that stem from the names of people or places or refer to particular events in history.
Some fantasy novels have even gone so far as to put a “translators” note in the beginning of their books, as if they really have been translated from a foreign language. This gets around those hyper sensitive readers who like to nit pick the use of certain words, but it’s not necessary by any means. Most fantasy readers take this as a given.
Go back through some of your fantasy stories and examine the language you use. Considering the translation concept, would you change anything? For writers always getting called out for using out of place words this is a helpful tool. For those who like playing with language, it can provide infinite possibilities for world-building.