Soliloquies and asides are both short speeches made by a character in a play. They are similar, but there are some distinct differences between them.
A soliloquy is a speech given by a character in a play who is alone on stage, usually to reveal their inner thoughts. An aside is a short comment made by a character in a play to the audience, usually to reveal their true feelings about another character or the situation they are in. Soliloquies tend to be longer and more detailed than asides, especially when they’re used to reveal a character’s inner thoughts or advance the plot of the play. A soliloquy might not actually be spoken aloud at all; it could instead be written on paper or even just thought silently.
Soliloquies can also be spoken by multiple characters at once, while asides are typically only spoken by one character at any given time. Soliloquies tend to be spoken in the first person (for example: “I’m so nervous!”), while asides are usually spoken in the third person (for example: “She’s so nervous!”).