When faced with someone playing their music too loud, one character says, “Would you mind turning that down a little please?” While a different character shouts, “If you don’t turn that shit down right now, I’ll fucking do it for you!” Straight away, we can differentiate the characters and not only surmise something about each of them but also about their relationship with the person playing the music. These characters employ their dialogue in very different ways — one polite, the other aggressive.
It's obvious that a cleaner on a generational spaceship woken from cryo-sleep to clean up after a bloody coup will speak in a very different way to a witch offering a potion to a lovelorn knight. The differences will exceed their locations, languages and accents. Almost everything will be different: the tone, urgency and rhythm of their speech; the vocabulary they use; the structure of their sentences. But what if it’s two cleaners woken from cryo-sleep? How can their voices be distinct?
The background of a character should be reflected in their voice. Their age, gender, culture, and education will influence their word choice. Think about the way older men often interrupt and speak over young women. The vocabulary of working-class people shouldn’t be simplified or dumbed down — but it should be used differently to upper management and company owners. In the same way, racist tropes should be avoided. It’s enough to say ‘She spoke with a French accent’, rather than…ow you say?…err…to write in ze way she en fait speaks…bah dis donc!
The temperament of a character influences not only the words they use, but the way they deliver those words. When they get angry do they shout and annunciate every single word? Perhaps they stutter when nervous or afraid? Much is revealed about a character by their tone of voice — are they arrogant or timid by nature? What happens when a character finds themselves outside their comfort zone? Do they talk more or go quiet? Are their sentences shorter or do their sentences trail off to silence? All of this tells us something about the character and sets them apart from the crowd.
Turns of phrase, tics, and slang are very effective in distinguishing characters, but they should be used judiciously and not over laboured. The same applies to habitually mispronouncing words. I once had a conversation with a woman who talked about visiting the ‘gully’ on an airplane, it took me a while to figure out she meant the ‘galley’. The same woman was someone who if a sentence only needed ten words, then she’d use thirty. If I was to write her as a character, the obvious foil to her verbosity would be to have a character who only spoke in clipped sentences, grunted or used gruff words.
Describing a character’s body language through narrative is another way of distinguishing their voice. Do their emotions play out on their face or are they unreadable? How a character walks and moves can tell us a lot about them and can differentiate them from other similar characters. Another physical attribute that distinguishes a character is their speaking voice. Is it low or high-pitched, raspy, booming or soft? The discordance of a character’s speaking voice being at odds with their physical appearance creates a unique and memorable character.
Every character, even minor ones, should have their own voice. One of the best ways to research character’s voices is to people watch. Sit in a café or a park or wherever people congregate and pay active attention to the conversations around you. Take notes.