This document summarizes a speech given by Jerome Bruner on the interrelationship between play, thought, and language in children. Bruner outlines several key functions of play, including that it allows for exploration without consequences of errors. He then discusses how play is used to socialize children into cultural values and potentially foster mental health, while cautioning against exploiting play for these purposes. The document concludes by describing an experiment showing that children who were given unstructured playtime with materials prior to a problem-solving task performed better, and argues that playful contexts facilitate language acquisition by encouraging experimentation without fear of error.