Somniloquy is the act of talking in one's sleep, while soliloquy is the act of talking while or as if alone.
As explained by the National Sleep Foundation, sleep talking, formally known as somniloquy, is a sleep disorder defined as talking during sleep without being aware of it. Sleep talking can involve complicated dialogues or monologues, complete gibberish or mumbling. The good news is that for most people it is a rare and short-lived occurrence. Anyone can experience sleep talking, but the condition is more common in males and children.
Sleep-talkers are not typically aware of their behaviors or speech; therefore their voices and the type of language they use may sound different from their wakeful speech. Sleep talking may be spontaneous or induced by conversation with the sleeper.
Tip! Learn Sleep Talking Causes and Treatments at WebMD.