Many influential thinkers who study the origin and development of knowledge talk deeply about the role of language. [[Jean Piaget|Piaget]] saw language as reflecting the child's cognitive development, that is thought comes first and language comes afterwards as a way of expressing their understanding of the world. Hence, language use can be observed to track developmental changes with the transition from egocentric to social language representing a transition from the preoperational to the concrete operationalise stage in the [[Piaget's theory of cognitive development|stages of development]]. Meanwhile, [[Lev Vygotsky|Vygotsky]] saw things in the opposite manner. That is, language originates from social interaction, and is increasingly used to guide the inner dialogue of the child. [[Noam Chomsky|Chomsky]] took a natavist view with the [[Language acquisition device|language acquisition device]], where humans are born with innate mental structures. Though what do we mean by language? Does it need to be natural? Do formal languages such as programming or mathematics count? What happens when we take principles from natural language acquisition and attempt to apply them to formal languages? ([[Seymour Papert|Papert]])