It can range from simple mumbling sounds to loud shouts or long, frequently inarticulate, speeches.
Their research suggests the following: Sleep-talking by itself is typically harmless; however, it can wake others and cause them consternation—especially when misinterpreted as conscious speech by an observer.
A sizable proportion of people without any episode during their childhood begin to sleep-talk in adult life.
Le Boeuf (1979) used an automated auditory signal to treat chronic sleep-talking in a person who had talked in his sleep for 6 years.
Lady Macbeth, in a "slumbery agitation", is observed by a gentlewoman and doctor to walk in her sleep and wash her hands, and utter the famous line, "Out, damned spot!
[12] Sleep-talking also appears in The Childhood of King Erik Menved, a 19th-century historical romance by Danish author Bernhard Severin Ingemann.
[13] In the story, a young girl named Aasé has the prophetic power of speaking the truth in her sleep.
In an 1846 English translation, Aasé is described thus: She is somewhat palefaced; and, however blithe and sprightly she may be, she is, nevertheless, now and then troubled with a kind of dreaming fit.
I do not give much heed to such dreaming now; but she has never yet said anything, while in this state, that has not proved in a manner true; though she can discern nothing, by night or day, more than others may do when they are in their senses.Walt Whitman wrote a now-lost novel based on Ingemann's romance, which he titled The Sleeptalker.