sentences:  Berk, Winsler, Diaz, Montero, Neal, Amaya-Williams, and Wertsch are amongst some of the current well-known developmental psychologists and researchers who have been specializing in the field of private speech.Although the concept dates back to the 1930s, private speech is still an emerging field in psychology with a vast amount of research opportunities.Evidence has supported Vygotsky's theory that private speech provides many developmental benefits for children.