Sarah Monette writes characters with the most vivid, characteristic voices I have ever read. Here’s her blog post on character voice and the influences of social class, profession, ethnicity and how to overthrow the polite ‘rules of fiction’ and get down and dirty with it.
An example, using a low-class assassin from one of her books.
Version 1:
“We met in the Orange-Tree, a tavern in Ramecrow that catered to the demimonde. I didn’t know how she had gotten my name, but it was no difficult task if you knew the right people to pump. My livelihood depended to a certain extent on it being possible for determined people to find me. And Ginevra was nothing if not determined.”
Version 2:
“I met Ginevra Hardesty in the Orange-Tree in Ramecrow. She’d left a message with the bartender at the Hornet’s Nest that she was looking for a cat burglar. If I was interested, Doris said, go to the Orange-Tree at the second hour of the night on 10 Pluviôse—only Doris was an awful snob and called it seven o’clock. At that end of winter, let me tell you, I was interested in just about anything.”
Version 3:
“I met Ginevra Thomson in the ordinary way of business. She was looking for a cat burglar. I was looking for a client. Meet at the Glorious Deed in Ramecrow, second hour of the night, 10 Pluviôse. Ain’t where I’d choose, but I said okay. The Glorious is tacky, but it is a real bar, not like in Dragonteeth, where you feel like you’re stuck in the theater scenery for all the slumming flashies and the demimondaine. And I ain’t good scenery for that kind of play.”
The evolution of a character’s voice