Cases of word usage

1) informal conversation (chitchat)

2) (of words, phrases, style) belonging to, suitable for, ordinary conversation and not formal or literally (colloquial)

3) (writing in the form of) a conversation or talk (dialogue)

4) a conversation between two people (duologue)

5) to listen secretly to a private conversation (eavesdrop)

6) a scene in a play in which only one person speaks; any long talk by one person in a conversation (monologue)

7) to hear (a person, conversation etc) without the knowledge of the speaker(s), deliberately or by chance (overhear)

8) words, phrases, meanings etc sometimes used in very informal conversation but not suitable for writing or for more formal occasions (slang)