People talk in their sleep, a condition known as somniloquy or sleep talking, because part of the brain does not fully transition into sleep mode, causing it to enact behaviors typical of wakefulness while asleep. This can happen during any stage of sleep, including REM and non-REM sleep, and often occurs during transitions between sleep stages or partial arousals. Factors such as stress, anxiety, genetics, sleep deprivation, certain medications, and sleep disorders can influence sleep talking. It may also be linked to other parasomnias like sleepwalking or REM behavior disorder. Though common and mostly harmless, sleep talking can sometimes be a sign of underlying conditions if frequent or accompanied by other troubling symptoms.