A Character's Vocabulary

    Vocabulary. An array of applicable words. It's great/fantastic/magnificent for a person/individual/soul to have an extensive/vast vocabulary. With it you can appeal to many different kinds of people.
    In fiction though, I think it's important to limit a character's vocabulary.
    Only to a certain degree. The way a character talks partly shows their personality and their upbringing. For example, a creative person might use analogies a lot to describe something, and a character who wields sarcasm like a weapon might make up his own phrases and nicknames. In addition, a person's accent might also change the way they pronounce words, and they could use terms that would be completely foreign to a person in another location.
    The way characters talk and the words they speak can help shape what they're like; but if a character uses different kinds of phrases (like telling someone "dunno" in one chapter and saying "I haven't got the faintest clue" to the same person in the next scene), it can be out of character. Including if the figure of speeches are out of context with the time period/setting of the story.
    What kind of vocabularies do your characters have? Do they have a favorite catchphrase?