Is “OK” Okay?

I am writing a fantasy fiction novel. At times in the book I used the colloquial term “OK” in dialog. I did this with full knowledge that “OK” is generally considered to not be OK in fiction other than recent contemporary fiction.

The reason for that is because the etymology of the term “OK” or “Okay” can only be traced back a hundred years or so. There are conflicting etymological explanations for the origin of the term, but none of them show “OK” being used by, for example, medieval knights. It is a thoroughly twentieth century colloquialism.

So why does “OK” appear in my book which is set in a sort of neolithic/bronze age setting?

For the same reason that I am writing in English. It should be obvious to anyone reading a fantasy book set in a world that has no connection whatsoever to actual, historical earth, that nobody in that world is speaking English, or any other language known on earth. The language they speak would be pure gibberish to earthlings, ancient or modern.

But colloquialisms make for smoother, more casual reading. So just as my writing is effectively translating non-existent languages into English, my writing also translates certain casual colloquialisms into English colloquialisms because that’s what readers understand.

I know that this is something that some writers and most editors will disagree with. But I’m not writing for them. I’m writing for people who want to read something that flows. And “OK” flows.