Some people dream during sleep, some people wake up suddenly during sleep, some people move unconsciously off the floor, and some people experience talking during sleep, also known as somnambulism. Somnambulism is generally a very common phenomenon and has been experienced by many people. Human sleep can be divided into two phases: non-REM sleep and REM sleep, which alternate, and non-REM sleep can be divided into four phases: sleep onset, light sleep, moderate sleep and deep sleep. During sleep, the activity of all organs of the body decreases, and the cerebral cortex starts to be in a state of inhibition, but some cells are still in a state of excitement, so if they establish contact with the nerve cells that control speech, the phenomenon of dreaming will occur. Common causes of dreaming are: 1, psychological factors: “day is thinking, night is dreaming”, if the heart is always thinking about a thing or work pressure, resulting in mental tension, emotional instability, may be dreaming; 2, physiological factors: such as too full or too hungry before bed, a lot of exercise and activity before bed, in the chaos and light 3, physical factors: long-term sleep talking is related to neurasthenia, dreams are subconscious reactions, some impulses and instincts in reality will be repressed, in the dream will be gradually released. In summary, many reasons can cause the phenomenon of sleep talking, as long as it does not affect normal life do not panic. Choose a comfortable sleep environment and develop good habits, which are all auxiliary to sleep.