[arebours]

I feel like you always have to bend the language to match the context. I think it was Sapkowski on his Narrenturm series (which happens to be set in the late Middle Ages) who said that even though he didn't want to specifically archaize the language he couldn't use a modern version of it either. Some new words/concepts like "computer" or "holocaust" would feel out of place and be immediately spotted by the reader.