monologue

One person speaking, though the term is generally understood to mean a virtuoso, highly skilful solo performance. Literary monologues are often set pieces in which a character reveals his or her personality, sometimes unintentionally (as in the dramatic monologue); in drama the soliloquy performs a similar function.

A monologue can occur in a dialogue; for example, in a conversation where one person suddenly launches into a lengthy anecdote.