Why do people talk in their sleep?
The key is whether our sleep has been disturbed.Sleep talking is thought to happen more easily in a mixed state between sleep and wakefulness. That is why it is said to be more likely when sleep is disturbed by too little sleep, stress, jet lag, or alcohol. Sometimes words from a dream come out loud, but not always. In most cases, it is said to carry little to no risk.
What is sleep talking?
Sleep talking means speaking out loud while asleep. Some people speak in clear sentences or even hold conversations, while others make mumbles or grunts that are hard to understand. According to Cleveland Clinic, a US medical center, about 2 out of 3 people talk in their sleep, and the person usually does not realize they were talking.
More likely when sleep is disturbed
Sleep talking is a type of "parasomnia," something unusual that happens during sleep. Events like this are thought to be a mixed state between sleep and wakefulness, so they are said to happen more easily when sleep is disturbed. Triggers include too little sleep, jet lag, stress or worry, and alcohol.
Are we talking about our dreams?
Sleep talking is sometimes related to dreams, but not always. Most dreams happen during a kind of sleep called REM sleep, but sleep talking can happen in any stage of sleep, both REM and non-REM.
A study of what sleep talkers say
In a 2017 paper, a French research team studied 883 episodes of sleep talking from 232 people. 59% were not words at all, such as mumbles, shouts, whispers, and laughs. The most common word was "No." When sleep talk did form words, its grammar was much like awake speech, and there were even pauses as if waiting for someone to reply. However, most of the people in the study had sleep disorders.
Reducing it, and when to see a specialist
To reduce sleep talking, experts recommend improving sleep quality, for example by going to bed and getting up at the same time every day and drinking less alcohol. It is advised to see a sleep specialist if sleep talking starts suddenly in adulthood, or if it comes with intense fear, screaming, or violent movements.
Based on advice from Cleveland Clinic.
Want to know more?
- The medical name for sleep talking is "somniloquy."
- In the 2017 study, men talked in their sleep more than women.
- People who talk in their sleep are said to have much lower sleep quality than those who do not.
Quick quiz: test yourself
When is sleep talking more likely to happen?
Show the answer
- When you sleep soundly
- When your sleep is disturbed
- When the room is very quiet
When your sleep is disturbed Sleep talking happens more easily in a mixed state between sleep and wakefulness, and it is more likely when sleep is disturbed by too little sleep, stress, jet lag, or alcohol.
Sleep talking happens more easily in a mixed state between sleep and wakefulness, and it is more likely when sleep is disturbed by too little sleep, stress, jet lag, or alcohol.
Next quiz ›Sources
- Talking in Your Sleep? Here's What That Could MeanCleveland Clinic（クリーブランド・クリニック）
- What Does the Sleeping Brain Say? Syntax and Semantics of Sleep Talking in Healthy Subjects and in Parasomnia PatientsSleep（PubMed 掲載の査読論文、2017年）
This article was written after checking the sources above as of 2026-10-03. Explanations may change as research progresses. Photo credits are shown below each photo.
