Private speech
Private speech is speech spoken to oneself for communication, self-guidance, and self-regulation of behavior. Children from two to about seven years old can be observed engaging in private speech. Although it is audible, it is neither intended for nor directed at others. Private speech was first studied by Lev Vygotsky (1934/1986) and Jean Piaget (1959); in the past 30 years private speech has received renewed attention from researchers. Researchers have noted a positive correlation between children's use of private speech and their task performance and achievement, a fact also noted previously by Vygotsky. It is when children begin school that their use of private speech decreases and "goes underground".