how does diction reveal someone's personality?

Question

when you read a book

Answer 1

a prim-and-proper person who obeys all the rules might speak more correctly, with better pronunciation and grammar, than a person who is more laid back. the laid back person might drop final g's (runnin not running, c'mon not come on) and use more slang. a rough personality might curse more. an innocent, guileless person might speak more like a child.

Answer 2

it can show if they get angry easily, their outlook on life, how they are feeling, what they think of other characters, if they are often sarcastic...things like that