Once upon a time in a small town called North Pole, I was knew a boy from Alabama. He moved to Alaska with his father and was very, extremely, terribly proud of being from the South. Big red truck, rebel flag, University of Alabama sweater, the whole nine yards. I knew him for years and slowly, slowly, slowly, he started to sound more like me. And my mentioning this one day infuriated him. It took me a few hours of the silent treatment to figure out why.
The way we talk is a part of who we are. It says where we come from, how our parents speak, how our friends speak, what kind of foods we grew up on, where we consider home. And it can and should be a large part of the 3D characters that live and breathe in our stories.
Consider these three ways to say the weather’s chilly:
“Brr! Rather nippy out today.”
“Whoo! It’s colder than a witch’s tit in a brass bra!”
“Zounds! ‘Tis bitter cold this winter’s morn.”
All the same language. But all very different. What conclusions might you draw about each of these speakers? (That middle one’s my dad, by the way, so judge kindly.) The way we speak can inject a lot of personality into even the most mundane exchange of information. So when your characters open their mouths to say something, keep this is mind and consider the following things that can add a lot of color to your dialog.
Dialect and Accent These are both largely products of region, but not necessarily. I knew a couple whose daughter decided she hated the Midwestern American accent she’d been born to and trained herself to speak with a south London accent. My rugby coach in college was born and partially raised in Arizona and then spent a few years as a kid in England, decided that accent was way sexier, and has clung to it ever since. But although those stories would both make for interesting background, most of us grow up speaking like those around us. So be aware of where your characters come from. (Since accent and dialect are heavily associated with pronunciations instead of words, this one can be a little trickier to get on the page, but it can be done. See the Redwall series by Brian Jacques for a fun example.)
Profanity (Swearing, Oaths, Obscenities) Everybody swears. Maybe we all do it very differently, but we all do it, making it an important part of character and world building. (“Mormon swearing”, by the way, is hilarious. Lots of ‘what the fetch’ and ‘oh my heck’ sort of silliness. It’s sometimes hard to tell how serious the speaker is. I’m talkin’ to you, Mom.) Like everything else about language, profanity is very culturally specific. Often, it is related to the religious system (thus profanity: making something sacred profane), but can be attached to much more mundane things, such as sex and various other bodily functions (thus obscenities: things that are obscene). So when your characters swear, whether that’s a lot or a little, powerful or silly, make sure that it makes sense within the context of their society.
Expressions (Sayings, Proverbs, Adages, Etc.) Raining cats and dogs. Apples and oranges. A frog in your throat. Kill ‘em with kindness. We know what all these expressions mean, even if they don’t make literal sense. These phrases have received a contextual meaning through generations of specific use detached from what each of the words actually means. Any natural language would have similar expressions, and so your characters should use them from time to time. Definitely make up a few, or even all, that exist in your speculative world, but not necessarily in, say, American English, or whatever your mother tongue may be. (And if you are making up your own, be sure their meaning can be derived from context and that they don’t feel forced.)
Pet Names and Nicknames I had a friend in middle school who called everyone younger than thirty ‘hon’. Friends, strangers, even teachers on occasion. It drove me nuts. I think it drove everyone nuts. I think that’s why she did it. (Also, because she couldn’t be bothered to learn people’s names, so blanket pet names worked just as well.) I’ve never heard of a culture that doesn’t have cutesy little replacement names for those they are close to (or those that they’re making fun of), so your characters should use them to. What does your MC call his partner? His children? His boss when she’s not around? (This section could, if this is an issue in your book, include slurs and insults, and other “nicknames” based on prejudice and bigotry. A lot of these sorts of words can double up in the profanities section as well.)
There is, of course, much more that goes into the what, why, and when of the things we say. But considering these elements of spoken language can, without every going into a character’s background, reveal a ton about who he or she is.