Definitions for "Language acquisition device"
In Chomsky's terminology, an inborn mechanism that enables children to infer linguistic rules from the language they hear. (140)
The LAD is a hypothetical mechanism in the human brain that enables any normal human to learn any of the 5000+ human languages (or any possible human language). Its existence has never been empirically demonstrated and, within the present approach, it would seem to be unnecessary to assume any LAD as a distinct, self-encapsulated unit.
A theoretical device that one is born with inside one's mind that allows a person to learn language.