A speech delivered by a character who is alone on the stage is

A speech delivered by a character who is alone on the stage is called a "soliloquy". It is a technique used in plays and drama where a character speaks their thoughts aloud, revealing their innermost feelings, emotions, and motivations to the audience. The character is essentially talking to themselves and is not aware that anyone else is listening. Soliloquies are often used to provide the audience with insight into a character's personality and to advance the plot by revealing important information.