Well, here are a dozen other real-people traits that are discussed in length in The Theatre Student, Playwriting by Peter Kline, that can improve characterization through dialogue:
1. Use of subordination:
Some people are good at organizing five or six ideas in one sentence. For example, 'I remember when I was young, my father would take us fishing early in the morning, and whilst we dangled our legs over the pier and watched the sunrise, he would tell us stories about the old fisherman who built this town.' Other people try and fail: 'When I was young, maybe five or six, Dad would take us fishing, and we watched the sunrise - we'd be sitting on the pier, see, and, anyway . . .' Some people use conjunctions to string ideas together: 'I was young and Dad would take us fishing and we sat on the pier and watched the sunrise and Dad would tell us stories.' Other people stick with one idea at a time: 'We were kids, yeah? Boy, Dad used to go on about the old geezers.'
2. Use of imagery:
Remember the different ways people learn? Those who aren't fond of the good old textbooks might like visual, audio, or hands-on media. The same applies to how people speak. Kline suggests that original and spontaneous people tend to use imagery in language. One of the senses usually dominates, but some people naturally combine sight, sound, and textual experiences (called synesthesia) and express these in language.
3. Irony vs sentimentality:
Getting a sarcastic or cynical character together with a sincere one can lead to sparkling, conflict-filled dialogue.
A: What a beautiful night.
B: Yeah, if you're into mosquitos and midges.
Some people just 'get it' while other people need everything spelled out before they understand the logic behind what the other person is saying. Classic one-liners are often spoken by acute thinkers and talkers. But be careful of characters delivering the perfect line every time. Most real people just can't do that.
5. Thinking vs reacting:
A: I'm gonna kill 'im.
B: Now hold on a second, Bill.
A: That no-good slime-bag stole my wallet.
B: You need to be sure before you go accusing him.
Some people say it straight. Some people tap dance around the point.
A: How are you?
B: Well, I was woken up at 5 A.M. by the blasted dog next door, and then I realized I'd forgotten to buy more coffee, and . . .
Have you ever listened to a person who sounds almost musical when they speak? Some people are naturally sensitive to the sound of words. Kline gives this example: 'I don't think I want to,' compared with, ' 'Twouldn't hardly be worthwhile.'
8. Use of clichés:
Some people have a cliché for everything: 'Oh well, whenever you get lemons, you can make lemonade, you know?' Although it's not a good idea to flood dialogue with clichés, a character prone to their use is one who takes himself seriously and uses clichés so that others might take him seriously too. It is an attempt to appear wise without taking the trouble to think (which is not always laziness, says Kline, but human nature).
9. Word play:
Just as some people are good with the sound of words, others are quick to apply clever double meanings to words, often for dramatic effect. Shakespeare was, of course, the champion at creating characters with this trait. Unless you're writing a piece where cleverness is a central element, word play in dialogue should be used sparingly. Kline suggests that a character prone to word play often uses morbid humor to demonstrate that the world is a sick joke that shouldn't be taken seriously. Kline offers Hamlet as a fine example here.
10. Whimsy, playfulness, and childishness:
The whimsical character is happy and imaginative and likes to have fun, usually by varying the tone, rather than words in her speech. She might indulge in pseudopoetry, or baby talk, or make deliberately silly statements to lighten the situation.
11. Exclamatory quality:
A: Dead! No way!
B: It happens to all of us, I guess.
A: I just can't believe it.
Some people talk about themselves a lot, and other people don't. Two people must quickly establish how personal they want their relationship to be at any given time. Some people will tell you their whole life story in three minutes, and other people remain aloof for years. Misaligned or misunderstood boundaries relating to personalization can lead to embarrassing or irritating situations. All good stuff for storytellers.
Peter Kline suggests 78 more elements that affect how people use words. See how many you can think of (no points for the obvious like age and education).