Despite what you may think and particularly if you are male, there is a high probability that you are suffering a relatively mild sleep disorder - somniloquy. More commonly referred to as sleep talking and affecting more than half the population each year, this phenomenon may occur at any sleep stage without the speaker being aware of it. Men and children typically experience a higher incidence of this condition, which is more likely to cause embarrassment than be physically harmful. Unless they disturb sleep partners, sufferers are rarely aware of their nocturnal ramblings.
Sleep talk may resemble a perfectly coherent conversation, utter nonsense or merely indistinct murmurs and groaning. Volume and pitch may also vary, with vocal sounds bearing no resemblance to the speaker's normal voice. When it comes to the topic of conversation, again, expect wide and varied content. Recent experiences and relationships are as likely to be covered as those long past with no definable significance. Both modern sleep science and the law agree that sleep talkers are unlikely to have any knowledge of their actions. As conversations do not stem from a conscious or rational mind, rest assured that any content is generally unable to be used as evidence.
As to what causes sleep talking, there are number of culprits. High up the list are lack of sleep, stress and depression. Other recognised triggers include alcohol and drug use. Although an occasional sleep chat is unlikely to disrupt your routine dramatically, if you find yourself constantly waking exhausted or your ramblings are accompanied by other more serious symptoms, consult your doctor.