Nobody knows exactly what causes sleep talking, but it runs in families, often appears alongside other sleep behaviours such as sleepwalking, may be triggered by stress, and can be a symptom of another sleep disorder. Sleep talking, or somniloquy, is talking out loud during sleep without being aware of it. It is very common: an estimated 60% to 65% of people talk in their sleep at some point. On its own it is harmless, but new or frequent sleep talking in adulthood can be a sign of another sleep disorder.
Sleep talking can happen in REM or non-REM sleep. The REM sleep calculator shows when your REM periods are likely to fall tonight.
What Is Sleep Talking?
Sleep talking is a parasomnia, a sleep disorder involving unwanted behaviours during sleep. A sleep talker speaks out loud while asleep; a listener may or may not understand what is said. The words are usually harmless and may make no sense at all, although sometimes they are rude or offensive. The talking can happen many times a night and can be loud enough to disturb a bed partner or roommate (AASM Sleep Education).
Episodes are usually short, often just a few words or sentences, and the sleeper rarely remembers them in the morning. Reports of sleep talking usually come from a family member or partner (Sleep Foundation).
What Causes Sleep Talking?
Experts are not sure exactly why people talk in their sleep (Sleep Foundation). What is known points to a mix of genes, stress and other sleep problems:
| Factor | What the evidence says |
|---|---|
| Family history | Sleep talking appears to run in families (AASM) |
| Other sleep behaviours | In twin studies it often occurs together with sleepwalking, teeth grinding and nightmares, which may share a genetic link |
| Stress and mental health | May be triggered by stress; it seems more common with mental health conditions, especially PTSD, although most cases are not linked to mental illness |
| Another sleep disorder | Sleep talking itself is benign, but it can be a symptom of another sleep disorder (AASM) |
The family, twin and mental health findings are summarised by the Sleep Foundation. Because sleep talkers are rarely aware of it, the true causes are hard to study.
How Common Is Sleep Talking?
It is one of the most common things people do in their sleep.
| Group | Figure | Source |
|---|---|---|
| Everyone, at some point in life | About 60% to 65% | AASM |
| Adults in Norway, ever | 66.8% | Bjorvatn et al., 2010 |
| Adults in Norway, in the last 3 months | 17.7% | Bjorvatn et al., 2010 |
| Young children | About 50% | AASM |
| Adults, regularly | About 5% | AASM |
The Norwegian figures come from telephone interviews with 1,000 randomly selected adults (Bjorvatn et al., Sleep Medicine 2010). Sleep talking occurs at the same rate in men and women (AASM). It is most common in childhood and adolescence and becomes less frequent in adults.
What Do People Say When They Sleep Talk?
The largest study of recorded sleep talking analysed 883 speech episodes from 232 adults during overnight sleep studies, most of whom had a parasomnia (Arnulf et al., Sleep 2017):
| Finding | Result |
|---|---|
| Non-verbal sounds (mumbles, shouts, whispers, laughs) | 59% of utterances |
| Most frequent word | “No” |
| Clauses that were negative | 21.4% |
| Episodes with questions | 26% |
| Clauses with profanity | 9.7% |
Understandable sleep talk followed normal grammar and even paused as if waiting for the other person in a conversation to reply. Men sleep-talked more than women in this group and swore more often.
Is What You Say When Sleep Talking The Truth?
Not reliably. Nothing in the research cited here shows that sleep talk reveals truths or secrets. The sleeper is not aware of speaking, and what they say may have no clear connection to their life, recent events or past conversations. Some sleep talk may relate to dreams, but not all of it appears to be tied to dreaming (Sleep Foundation). Much of it is mumbling rather than words, and the recording study described understandable sleep talk as mostly a tense conversation with unheard others, suggestive of conflicts (Arnulf et al., 2017). If something said in sleep worries you, talk about it awake rather than treating the words as evidence.
Does Sleep Talking Happen In REM Or Non-REM Sleep?
Both. Unlike most parasomnias, which are tied to one part of the night, sleep talking can occur in any stage of sleep, and it is still unknown whether it is closely linked to dreaming (AASM). In the 2017 recording study, negations, questions and swearing were more common in non-REM sleep, while longer verbal abuse occurred more in REM sleep.
Is Sleep Talking Dangerous?
In most cases, no. It does not usually affect the sleep talker’s own sleep much. Problems come from its effects on others or from what comes with it (Sleep Foundation):
- A bed partner or roommate may lose sleep.
- Embarrassing content can cause stress between partners.
- Sleep talking that occurs with nightmares or sleepwalking may be part of a bigger sleep problem. Read more about sleepwalking and nightmares.
Sleep Talking vs Other Night-Time Noises
| Behaviour | What happens |
|---|---|
| Sleep talking | Words, mumbling or conversation; usually brief and harmless |
| Catathrenia | A breathing disorder that causes long groaning sounds while breathing out |
| REM sleep behaviour disorder | Acting out dreams physically, often with shouting, punching or kicking |
| Snoring with pauses | Loud snoring, gasping or choking; can be a sign of sleep apnea |
The first three are described by the Sleep Foundation. If loud snoring and gasping are part of the picture, check the warning signs with the sleep apnea risk calculator.
How Can You Stop Sleep Talking?
Because the cause is not fully understood, there are no proven ways to stop sleep talking, and in many cases no treatment is needed (AASM). Sensible steps are:
- Keep a regular sleep schedule and get enough sleep.
- Manage stress with a calm wind-down before bed.
- Avoid stimulants and electronics before bed, which may help reduce episodes (Sleep Foundation).
- Treat any other sleep problem, because when sleep talking is a symptom of another disorder, treating that disorder is the answer (AASM).
For partners, earplugs and a white noise machine can mask the noise (Sleep Foundation).
When Should You See A Doctor About Sleep Talking?
Talk to a doctor if sleep talking becomes more frequent, starts for the first time at an older age, or comes with other symptoms such as limb movements or daytime sleepiness (AASM). Also seek advice if sleep talking comes with shouting and violent movements, sleepwalking, loud snoring with gasping, or frequent nightmares.
See when your REM periods fall with the REM sleep calculator.
Sleep Talking FAQs
Is It Normal To Talk In Your Sleep?
Yes. About 60% to 65% of people talk in their sleep at some point, and about half of young children do.
Why Do I Talk In My Sleep All Of A Sudden?
Stress and poor sleep may trigger episodes. If it starts in adulthood or comes with other symptoms, see a doctor to rule out another sleep disorder.
Can You Have A Conversation With A Sleep Talker?
Sleep talk can sound like one side of a conversation, but the sleeper is not aware of it and usually will not remember it.
Is Sleep Talking Linked To Dreams?
Sometimes it may be, but sleep talking happens in all stages of sleep and it is unknown how closely it is tied to dreaming.
Should I Wake Someone Who Is Sleep Talking?
There is no need. If it is keeping you awake, earplugs or white noise usually help.
Do Children Grow Out Of Sleep Talking?
Usually. It is common in young children and becomes much less frequent in adults.