I understand that when writing a novel about a specific region of the world, it's irritating to others to read it in the dialect of that particular area. When writing about a specific region set centuries ago, however, I'm unsure how best to present it. I get the feeling that writing about 18th century London in a modern tone would have the same anachronistic effect as going to a Renaissance festival and seeing one of the peasants wearing a watch. On the other hand, I don't want to resort to using the language of that time and confusing a modern audience.What's a good way to approach this to still give the feel of the time period? Write with a modern style but still throw in words and phrases of the time? Any advice would be appreciated.

Advice from the Evil Editor here.