The issue of accuracy in historical fiction is one I'm often asked about. Does the word 'fiction' give a writer licence to ignore historical detail where the story demands it, or should the story be moulded to fit within the known facts, perhaps with a resulting lack of drama?
When people talk about historical inaccuracy, they are usually thinking of outright anachronisms – medieval serfs scrubbing germs off potatoes, or a Tudor apothecary doing CPR. Often, however, it's not that black and white. If I wrote a full exploration of historical accuracy in fiction it would be somewhat too long for a blog post, so I'm going to concentrate today on dialogue – an aspect where getting it 'right' can actively thwart your chances of creating a novel that works.
Let's take an extreme example, and say your book is set in Roman Britain. Are you seriously going to have your Roman characters talking in Latin? What about your heroic underdogs from various Celtic tribes? The likelihood of a significant number of modern readers been well-versed in each of these languages is slim, to say the least. Historical accuracy, in this instance, would prevent the novel ever reaching an audience. Even in the event of someone desperately wanting to read in Latin and Iceni, they would never get the chance because no publisher in their right mind would take it on.
Less extreme dialogue issues crop up for other historical periods – in my first book, set in 18th-century Chester, I had to consider a regional dialect that even people in other parts of the country at the time wouldn't have understood. An exact rendering of the way people spoke would at best slow down the flow of the story and at worst leave readers wondering what on earth was going on. More generally, using thees and thous, forsooths and do-not-yous – although perhaps perfectly accurate to the time your novel is set – can now look clichéd and forced.
On the other hand, to have characters speaking in an identifiably modern voice is equally unsatisfying (although it can be done successfully for comic effect). Dialogue needs to meet the reader's expectations of what is 'historical' without annoying them or making them flick back to a glossary every few lines.
My way of doing historical dialogue is to let myself go completely overboard in the first draft. I don't care how archaic or regional the dialogue sounds – I put whatever instinctively feels right, and at that stage, no one is going to read it anyway. I just bung in as many unusual words and colourful slang as I feel like – it's fun! Later, during the editing process, I replace many of the obscure terms but keep the sentence structure. This is like excavating the bare bones of the speech patterns, so that the dialogue is accessible but still clearly not of our own time.
On occasions, however, a word not in modern use is the perfect word for a character to use, and in these instances I am all for including it. Usually it's possible to make the meaning clear from the context, and most readers are intelligent enough to work it out. (And if not, well... there's not much you can do for some people!)
Writing historical dialogue is not about being historically correct but about using sleight of hand to create an illusion. You have to find the balance that makes the dialogue unobtrusive, so that it fits in so well – it's just so obviously how the characters would speak - that it doesn't even excite comment on whether or not it's accurate. And with that, forsooth, 'tis time for me to ende this blogge-poste and let thee wende forth thy merrie waye.