Your fictional characters should be as different from one another as the real people in your life. One way to show differences is in their voices.
Years ago, returning home from Aqua Zumba, I drove past Hermann Sons Hall and remembered the German woman who managed the building as if it were her immaculate residence. On our early morning walks, my husband and I watched as she polished door knobs, washed windows, and replaced gravel in the driveway. Her mission was to keep “her” building spotless. You didn’t want to cross her.
How does a writer establish “voice” for characters?
If your character is a stoic German woman who manages a building as if it were her pristine cottage, picture what she looks like. Short hair, stern features, sensible shoes, tailored clothing. Then you can imagine what she sounds like: sharp, clipped sentences, uses precise words sparingly.
Contrast that with a Mother Goose type: round in looks, ample lap for children to sit on, laugh lines forming parenthesis around her mouth, her eyes crinkle with merriment. She might talk softly or slow. You can hear the smile in her sugary voice.
Write a scene showing two characters’ personalities using dialogue.
For more on writing about character: Three-dimensional characters . . . Prompt #444 on The Write Spot Blog.