I'm still interested in modern/versus archaic language in historical novels. I really think I ought to qualify archaic and say less modern, or language more true to the time period of the novel. Possibly not even that. If I wrote a book in the language used by Elizabethans, I doubt it would sell very well. But conversely, is it OK to write a book set in Elizabethan times and uses phrases like "She was drunk as a skunk and well out of order...." I wonder.
Trawling the web, I found this snippet from writer Mary Renault. Her books The King must Die and Bull From the Sea fuelled my imagination when I was much younger and I still have them on the shelf today. This is what she said on the topic:
"Greek is a highly polysyllabic language. Yet when writing dialogue for my Greeks I have found myself, by instinct, avoiding the polysyllables of the English language, and using, as far as they are still in the living language, the older and shorter words. This is not because the style parallels Greek style; it is entirely a matter of association and ambience. In Greek, polysyllables are old; in English, mostly Latinised and largely modern. They have acquired their own aura, which they will bring along with them. Their stare, like that of the basilisk, is killing. Take the following sentence, which I have just picked at random from a magazine: “High priority is to be given to training in the skills of community organizing and conflict resolution.” It contains no concept which Plato did not know, or, indeed, did not in fact deal with. But it comes to us steeped in notions of the company report, the social survey, and so forth. When I see writing like this in a historical novel I know what the author is after. He wants us to identify with the situation of his characters as if it were our own. But it isn’t, and identification thus achieved is a cheat. You cannot, as an advertising copywriter would say, enjoy a trip to fifth-century Athens, or Minoan Crete, in the comfort of your own home. You have, as far as your mind will take you, to leave home and go to them."
I totally agree. The trick is to find the right kind of language for the particular era in which you wish to write your novel.