Are “sleep dreams” audible?

Krishna: Some people talk in their sleep. Sleep talking, or somniloquy, is the act of speaking during sleep. It's a type of parasomnia -- an abnormal behaviour that takes place during sleep. It's a very common occurrence and is not usually considered a medical problem.

Many people talk in their sleep. Half of all kids between the ages of 3 and 10 years old carry on conversations while asleep, and a small number of adults -- about 5% -- keep chit-chatting after they go to bed. I heard my niece and nephew talking in their sleep but they are children. They themselves don’t know whether they are dreaming while sleep-talking.

But does sleep talking occur during dreaming? Scientists still are not sure if such chatter is linked to nighttime dreams. There’s some evidence that, at times, sleep talking may be related to dreams, but this is not always the case. The talking can occur in any stage of sleep. Most dreams happen when you’re in the deep, rapid eye movement (REM) phase of sleep. But sleep talking can happen during any stage of sleep, including both REM and non-REM sleep.

REM sleep behaviour disorder (RBD) and sleep terrors are two types of sleep disorders that cause some people to shout during sleep. Sleep terrors, also called night terrors, usually involve frightening screams, thrashing, and kicking. It's hard to wake someone having a sleep terror. Children with sleep terrors usually sleep talk and sleepwalk.

People with RBD yell, shout, grunt, and act out their dreams, often violently.

Sleep talking can also occur with sleepwalking and nocturnal sleep-related eating disorder(NS-RED), a condition in which a person eats while asleep.

When I was in school one day I was very tired after a hectic school schedule and slept at about 6pm. in the evening. I dreamt about a tiger attacking me. I started screaming and got up from the bed while still dreaming in the sleep state. My sister who was sitting and studying beside me thought I was ‘possessed’ by a devil and started screaming too. My parents came running and woke me up. I remembered the dream and told them what had happened. I don’t have any sleep behaviour disorders though. It was just a one time incident.

Things that can cause sleep talking include some medications, emotional stress, fever, mental health disorder, narcotics, and alcohol.