Somniloquy

Somniloquy, commonly known as sleep-talking, is a parasomnia in which a person speaks aloud while asleep, ranging from simple mumbling sounds to loud shouts or long, frequently inarticulate speeches. It can occur multiple times during a single sleep cycle, and during both non-rapid-eye-movement and rapid-eye-movement sleep, though like sleepwalking and night terrors it most commonly occurs during deep, delta-wave non-REM sleep or during temporary arousals from it. When somniloquy occurs during REM sleep, it represents what researchers call a motor breakthrough of dream speech, in which words spoken within a dream are spoken out loud; because all motor function is normally disabled during healthy REM sleep, REM somniloquy is usually considered a component of REM sleep behavior disorder, and depending on its frequency it may or may not be considered pathological.