In language acquisition theory, theinnatist theory (introduced by Chomsky) is the idea that humans are born with an innate capacity to process and acquire language. This capacity is called the language acquisition device (LAD). The theory holds that all languages have an underlying shared set of structural rules (Universal Grammar), which the human brain is naturally equipped with. The theory is widely accepted though it has been questioned in recent years (even by Chomsky). See for example Vyvyan Evans' The Language Myth.