Somniloquy is basically the act of someone talking in his or her sleep, which can occur during any stage of sleep. Such talking can range widely, from quiet whispers and mumbling to clear and eloquent speech. Even yelling or screaming may occur during such vocalization. As long as such speaking occurs in relatively small amounts and is not disrupting others, it is considered perfectly normal and is not necessarily a sign of any sort of sleep disorder. Somniloquy can be part of other sleep disorders, however, including lack of sleep and even night terrors.
Also simply referred to as sleep talking, somniloquy is a fairly common event that occurs for many people as they sleep. Words spoken and ideas expressed during sleep talking can include just about anything, from short nonsensical whispers to loud outbursts of vulgarity or profanity. The person who experiences somniloquy usually has no memory of what he or she says while sleeping, and comments made during such sleep talking should not be considered representative of any conscious thoughts or ideas.
Somniloquy can occur during just about any stage of sleep, including non-rapid eye movement (NREM) sleep and deeper rapid eye movement (REM) sleep. Since this can occur at different points in the sleep process, the words spoken can represent a wide range of ideas and stem from different events. Someone who is not yet dreaming may simply speak gibberish in his or her sleep, while another person in deeper sleep could speak out loud words that are being spoken in a dream.
Sleep talking is not necessarily considered indicative of a sleep disorder, and is not considered a sleep disorder itself. As long as such talking is not overly disruptive to others sleeping nearby, it is typically nothing that should create concern. Most people are likely to speak or make noises occasionally during sleep, though ongoing somniloquy may be indicative of a larger problem.
Ongoing and long-term somniloquy may be indicative of a lack of sleep, and this can be caused by a number of factors such as excess caffeine or stress. There are cases in which people may speak while sleeping as a precursor or part of sleepwalking, which should be treated by a sleep therapist. Night terrors can also cause a person to scream or yell while sleeping, and such somniloquy can be fairly disquieting to others. In these instances, where sleep talking is indicative of a greater problem, then assistance from a health or sleep specialist should be considered.