ABSTRACT
A central goal of research on language acquisition is to explain the course of development: how the adult grammar is achieved on the basis of the linguistic input available to the learner. The knowledge that the learner brings to that task (including procedures for learning) often is called the language acquisition device (LAD). The linguistic input from parents and others is called the primary linguistic data (PLD). On the basis of these data, the LAD hypothesizes a series of grammars, the last of which is the adult grammar, or “final state.” The entire process is represented schematically in Example 1: https://www.w3.org/1998/Math/MathML"> Input (PLD) → LAD → Final State https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315799599/d8ad6985-9f7f-4087-a3d2-4f28820d5445/content/eqnD_1_B.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/>
