Language acquisition device

The Language Acquisition Device (LAD) is a claim from language acquisition research proposed by Noam Chomsky in the 1960s. The LAD concept is a purported instinctive mental capacity which enables an infant to acquire and produce language. It is a component of the nativist theory of language. This theory asserts that humans are born with the instinct or "innate facility" for acquiring language. The main argument given in favor of the LAD was the argument from the poverty of the stimulus, which argues that unless children have significant innate knowledge of grammar, they would not be able to learn language as quickly as they do, given that they never have access to negative evidence and rarely receive direct instruction in their first language.

A summary explaining LAD by Chomsky states that languages are infinite pertaining to the sequence of word forms (strings) and grammar. These word forms organize grammatically correct sequences of words that can be pooled over a limited lexicon of each independent language. So, LAD is tasked to select from an infinite number of grammars the one which is correct for the language that is presented to an individual, for example, a child.