Think with me for a moment about all the different ways people talk. Not only do we have many different languages in this world, but there are also so many different dialects within the languages, sometimes just subtle differences, even. And narrowing it down even farther, even slighter differences, like a preference of one word over another in different states!
I'm a Michigander, born and raised there for 10 years. In Michigan, carbonated beverages are referred to as 'pop', while here in Arizona where I currently am, it's called 'soda'. Not a very big difference or anything to truly make that much of a fuss about, right? But I still call it 'pop', because that's what I grew up with. :) To me, 'soda' seems more like a float or something, with ice cream or something else in it. Haha, but I'm getting off topic here...
Now, let's look at making character voices distinctive. You might automatically think, since it's not really possible to 'hear' a southern accent vs northern accent in a book, that all of a sudden ya gotta start fillin' yer dialogue with all them over th' top southern words ta give it that distinctive twang. Und Germans vil speak like this, vat else vould you do? Et cetera...
But, the thing is, if you start messing up the dialogue too much, you'll begin to distract from the actual words, which is exactly what we don't want to do. And you want to know a secret? You don't have to be so over-the-top to achieve distinctive character voices! In fact, subtlety is better than over-the top!
(NOTE: Yes, if you have a character with a really thick Southern accent, especially if you want to show the distinction, feel free to add a few more grammatical changes to the dialogue. Just don't overdo it and you'll be fine. :)
Again, look at the real world. I'm sure you have to have friends from many different places, right? Have you ever paid close attention to the differences in their speech patterns? Maybe one of your friends, like, say 'like', like, a lot, or you have a friend who refers to a group of people as "y'all". It's the little things like this that make everyone's voices so distinctive, and therefore exactly what we should apply to writing our characters. :)
To be honest, I never really realized how much such subtle changes could make your dialogue come so much more alive until I read the Percy Jackson series, specifically Heroes of Olympus. There's a lot of jumping back and forth between 7 very different POVs, and yet any time it switches, I know exactly who's speaking without even looking at the chapter title (the name of the POV character)
Why? Because, although none of the characters have any very heavy dialects or extremely distinctive language differences, you just know who's talking, because you pick up on the subtleties of their individual personalities in their dialogue. You can hear the snarky I'm-so-clever tone based on a few word changes, or the more refined and proper tone of a different character. Just the way one of the characters reflects more heavily on 'I' and themselves or the way another character is always worried helps show who is speaking.
In fact, Percy Jackson was what inspired and challenged me to make my character voices more distinctive. I have some characters that sigh a lot, or say 'er' and stumble over their words, and some who do not use contractions as they do not understand their meaning, and even a little dragon who speaks like a young child! And when I heard people tell me that they loved my characters and could totally hear the differences in their dialogue, well, I was pretty pleased. :)
Oh, and here is a very important writing tip: All your characters should not sound like you, especially if they come from different places. Everyone's backgrounds, histories, and even personal experiences affect their speech patterns, if only just slightly, and you should analyze your characters to find these little language nuances for your own stories as well.
For example, you might have a character who always goes 'uh, you know' when they're nervous, or someone who refers to friends as 'mates' instead of friends. Maybe there's a story behind some of these, too, like the character's deceased father always used to use the phrase 'til the cows come home' even though no one else ever used that, and so your character adopted it as sort of a way to keep their father's memory alive.
See what I mean? There are so many different ways to make your characters' voices unique and distinguishable, and really, this is just the beginning! Another part of this that I slightly touched on on Wednesday is the way your characters' outlook on life and/or history will color their perception of life. An optimist and a pessimist don't see the world the same way, and someone who hates a character versus loves a character will also see them differently.
But truly, though I can give you many examples and ideas for making your characters voices distinctive, the best way to do it is simply by observing and experimenting. Try many things, from little word changes to entire dialect differences. See which best fits your characters, or where there may be opportunities to make their speech more unique.
In fact, here's a little exercise for you: find at least one (more is better!) unique language nuance that is already in your characters' dialogue, or create one for them. Remember, no one talks exactly the same, and it's the little differences that truly make them unique. :)
So, what sort of language nuances have you discovered or added to your characters' personalities?