Play
"In play a child always behaves beyond his average age, above his daily behavior; in play it is as though he were a head taller than himself. As in the focus of a magnifying glass, play contains all developmental tendencies in a condensed form and is itself a major source of development." (Mind in Society, 1978 posthumous)
Language
"Language is the tool of the tools." (AZQuotes.com)
"Thought is not merely expressed in words, it comes into existence through them." (AZQuotes.com)
