The Language Acquisition Device (LAD) is a theoretical concept proposed by linguist Noam Chomsky. It suggests that humans are born with an innate ability to learn language. This device enables children to understand and produce language naturally, regardless of the specific language they are exposed to during early development. According to the LAD theory, children can grasp complex grammatical rules and structures without formal instruction. This innate mechanism helps explain why language learning occurs rapidly in early childhood, as children instinctively apply rules they have not explicitly been taught, leading to the acquisition of their native language.