An answer from RG

Remittance Girl writes:

In first person, or third person limited, dialogue is a very important
tool for revealing not only the personalities of other characters, but
how they relate to your main character. People position themselves in
speech. And subtly, they position themselves in the terms of hierarchy
this way - sometimes in speech that on the surface holds little or no
important content. But this is how we establish comfort, commonality
and cooperation.

The study of this sort of dialogue has been undertaken at MIT for the
purposes of creating realistic AI interactive agents. Paper attached
for interest. (KB: I couldn't figure out to link to this, so you'll have to take RG's word for it, or contact her through her site. Interesting stuff if you're a geek girl like me.)

Obviously fiction requires that the characters get to the point a
little quicker than we do in real like, but it would be a mistake to
dispense with all the "weather talk". Because characters who come to
the point too fast, with strangers, lack realism.

The other thing worth considering is the non-verbal dialogue. Head
movement, body orientation, eye direction all serve to inform us of a
person's orientation towards us.



KB:
Dialog and body language is a powerful combination, even more so when
they're in conflict. Find href="http://www.remittancegirl.com/">Remittance Girl here. She has some incredible stories, some surreal, all amazing.