Many people think talking during sleep occurs during the dream, but scientists are still not sure whether this condition is associated with a dream or not because it can occur in any stage of sleep.
Some things are known to cause someone to talk during sleep, as quoted by WebMD, Wednesday (05/02/2012), namely:
A. Taking certain
2. emotional stress
3. Fever, especially if high fever
4. Have mental health disorders
5. Substance abuse or drug
This is usually done unconsciously by the person, in these conditions one could only whisper, speak normally, or even cried. This condition is sometimes a funny thing for people who see it.
Sleeping, talking or somniloquy is talking in his sleep and activity, including type of parasomnia (abnormal behaviors that occur during sleep). These events are very common and usually not considered a medical problem.
The words are sometimes issued with a clearly audible but can also be interpreted as a hard murmured. This condition is usually not more than 30 seconds, but can occur in some people talk in their sleep many times during the night.
About half of children aged 3-10 years of talking in his sleep and only 5 percent of adults who do. This condition is expected to decline in the family, although not known with certainty.
But if someone yell during sleep there are two things that might be the cause, the REM sleep behavior disorder (RBD) and sleep terrors.
To sleep terrors usually he shouted frightening, struggling and kicking, while RBD he yells, growls and acts like violence.