Looking back over my posts from 2008 I found this interesting snippet from Phillippa Gregory. Talking about writing, language and languages, she says:
"In terms of styles of language‚ I deliberately took the choice to use fundamentally modern language‚ but quite pure and quite simple. So I don′t use slang and I don′t use modern idioms. This is to make it acceptable to a wider audience and to write as well as I possibly can without being limited by language. For example‚ if I was to write a novel set in France and there were French people speaking French to each other − I wouldn′t put that on the page in French‚ I′d put it in English − and the reader understands as it′s part of a convention of reading a novel‚ that when someone is speaking Russian or French you don′t get a page of Russian or French − you get it in English.
If someone said to me that the past is a foreign country‚ it seems to me that it speaks a foreign language. So in terms of any notion of thee and thus and thy‚ superfluous words‚ I tend not to use them as it′s so strange to the modern eye. You also gain nothing by using them and the chances of rendering them correctly are very slim.
In the case of early modern society we don′t know how they spoke‚ we know how people have written down Shakespeare plays‚ but we don′t know how people actually spoke or what they sounded like. We do believe however that Anne Boleyn maintained the French accent throughout her life as she believed that it made her a bit special‚ I mention this in the novel. But in terms of how actually people spoke‚ we don′t know‚ so I won′t even make a guess."
This seems sensible to me, and maybe that is because it is the way i approach writing historicals, too. I allow some of the local Northumbrian dialect I hear around me every day to filter in where it is appropriate for the character and some Scots that is used today by my neighbours/and or heard on various trips north of the border. This isn't to try and add a historical edge to the story, but to help with characterization. Wander around Newcastle's main shopping street - Northumberland Street - any day of the week and you will hear refined BBC type accents rubbing shoulders with Geordie and all the stops in between. (Sorry, no pun intended)
Personally I dislike the accent that predominates in Eastenders and the one I find the hardest to "translate" is the Rab Nesbit Glaswegian. I hear echoes of Northern Ireland in Australia, and can hear differences in American speech without know where in the US the speech originates. The whole subject of language is a fascinating one.