The Language Acquisition Device, or LAD, is part of Chomsky's acquisition hypothesis. The LAD is a system of principles that children are born with that helps them learn language, and accounts for the order in which children learn structures, and the mistakes they make as they learn. Second language learning theory proposes that acquisition is possible in second and subsequent languages, and that learning programmes have to create the conditions for it.
One piece of evidence for the existence of a LAD is the fact that physical areas of the brain concerned with production and comprehension have been identified.
In the classroom
The belief that acquisition is possible lies at the heart of any method that involves engaging the learner in natural communication and authentic input, these include task-based learning, CLIL, and some story- and activity-based programmes.