We're currently working on dialogue at our monthly workshops. On Friday night, one writer, who is working on a series for his granddaughter, said all his teen girls sound the same.
So we worked on ways to make characters of similar ages that know each other sound different. Here are some ideas:
1) Emphasize their differences.
Even very similiar characters are not identical. One scene from Bryony I often read as an example has four girls in 1970's Munsonville hanging around in a bedroom talking about the mansion restoration and the rumors of it being haunted while Katie, who hopes to become a beautician, practices with electric rollers on Julie's hair. Three of the girls have grown up together in the village, and one is the new girl from the Chicago suburbs. None sound alike. Here's why:
One girl is smart, skeptical, and idealistic about her crush and unrealistic her future; one is goal-oriented, direct to the point of blunt, and open to supernatural possibilities; one is immature, easily swayed, and fearful regarding ghosts; and the new girl (our protagonist) is mostly listening and taking it all in.
Focusing on these differences will direct the dialogue. Why?
2) We all speak from our perspective.
Who we are as people, our personalities and interests, direct our words: what we choose to say (or not say), how we say it, when we say it, why we say it, and to whom we say it - and even the gestures we use when speaking.
Keeping this in mind will help you write dialogue that is specific to your character. Dialogue should never be a simple exchange of information because conversation is never that simple.
Here's part of the scene:
“Me neither,” Julie said. “The trouble with Munsonville is that no one thinks past fishing boats. I want something more than night crawlers and dead carp.”
“Like what?” Katie reached for the comb.
“Like anything that requires some brain power. Like a car, maybe.”
Melissa was surprised at Julie’s scornful remarks. She thought all the villagers lived contentedly in Munsonville.
Ann turned a page. “I’ll be too busy traveling around the world.”
Julie tossed her head and snorted.
“Hold still!” Katie struggled to fasten the roller.
“Not if,” Julie snapped her fingers, “Jack Cooper looked twice at you.”
Ann blushed, still looking down. “That’s not true. I’m marrying someone so rich and ambitious, I’ll own homes in three countries and eat gourmet food every night.”
“I’d rather get a job and make my own money, thank you.”
“Can’t you get a job?” Melissa then remembered Munsonville had no industry.
“Not unless you slave for a family business. My mom works the information desk at the nature center, and my dad sells used cars in Jensen. By the time they restore Simons Mansion, I’ll be in college, thank God.”
Katie rolled another strand of hair and secured it with a pin. “Do you think the ghost will attack once they start fixing it?”
Ann’s blue eyes were stern. “There’s no ghost. Grow up, Katie.”
Julie shook her head in exasperation and a roller fell out of her hair. “You’ve got to keep an open mind. What about the stories?”
“Mass hysteria,” Ann said.
“Maybe, except for the evidence backing their claims.”
Melissa stiffened and held her breath. Did Julie mean Kimberly?
Ann looked down her nose at Julie and snickered. “Not nutty Tina Swanson?”
"Who’s she?” Melissa said.
“Last summer,” Ann said, “Tina’s family rented one of the lakefront fishing cottages. No one liked Tina because she bragged that her red hair made her psychic, After a month, Tina’s parents went to Uncle Gabe. Tina said a dark man in black broke into her room while she was sleeping. So, he posted a guard.”
“Did they see anyone?” Melissa asked.
“Of course not,” Ann said, giving her a funny look.
“My parents said Tina was just spoiled and looking for attention,” Katie said.
“Or maybe she did have ESP,” Julie said. “Maybe everyone missed what she saw. How do you know nothing comes into your room at night?”
“I hope not!” Katie shuddered. “There. You’re free for fifteen minutes.
("Bryony," Chapter 10: When Good Dreams Go Bad)