What is the "language acquisition device" (LAD)?

The language acquisition device (LAD) is a theoretical construct introduced by linguist Noam Chomsky, which suggests that humans are born with an innate ability to acquire language. This concept posits that children have an inherent capacity or biological mechanism that enables them to learn the complex rules of language naturally and quickly, often without explicit instruction. This innate ability is thought to be critical during the sensitive period of language development, typically in early childhood, when children are especially receptive to linguistic input from their environment.

The LAD explains how children can understand and produce sentences they have never heard before by applying grammatical rules they internalize. This concept revolutionized the study of linguistics and child development by emphasizing the role of nature in language acquisition, contrasting with behavioral theories that focus solely on environmental factors and learned behavior. Recognizing the LAD helps to understand the universal patterns observed in how children around the world acquire language skills, despite the differences in linguistic environments and cultures.