Study Reveals Sleep Talkers Swear More, Men Curse More Often

Research into sleep talking has revealed that individuals often use negative and vulgar language, with men cursing more frequently than women. The study, published in the journal Sleep, found that nearly 10% of sleep-talking clauses contained profanity, and instances of the F-word occurred approximately 800 times more often during sleep than when awake.

Scientists utilized video polysomnography to record speech episodes from participants over two nights. They monitored the frequency of speech, the words used, and whether the tone was positive or negative, and if the remarks were directed at others. Of the 883 recorded speech episodes, 3,349 understandable words were identified, excluding mumbles, shouts, or whispers.

The most common word uttered during sleep was "no," accounting for 21.4% of clauses, predominantly during non-rapid eye movement (REM) sleep. Swearing was also more prevalent in non-REM sleep, while verbal abuse tended to be longer and more insulting during REM sleep.

A significant finding was the grammatical, semantic, and conversational structure of sleep talk, which closely resembled awake speech, including pauses that suggested expecting a response. This suggests that the sleeping brain can maintain a high level of cognitive function, comparable to wakefulness.

Sleep talking, also known as somniloquy, is a common parasomnia, with studies indicating that approximately two-thirds of people experience it. Other factors contributing to sleep talking include stress and certain medications. The phenomenon affects men and women equally.

Previous research has highlighted other sleep-related behaviors. For instance, a 2024 study in the Journal of Clinical Neuroscience found that women are twice as likely as men to engage in complex activities like handling electricity or kitchen tools while sleepwalking. That study also indicated that younger adults and children are more prone to sleepwalking than older individuals.