Knowledge and Learning in Natural Language

Abstract

The present dissertation is a study of language development in children. From a biological perspective, the development of language, as the development of any other organic systems, is an interaction between internal and external factors; specifically, between the child's internal knowledge of linguistic structures and the external linguistic experience he receives. Drawing insights from the study of biological evolution, we put forth a quantitative model of language acquisition that make this interaction precise, by embedding a theory of knowledge, the Universal Grammar, into a theory of learning from experience. In particular, we advance the idea that language acquisition should be modeled as a population of grammatical hypotheses, competing to match the external linguistic experiences, much like in a natural selection process. We present evidence—conceptual, mathematical, and empirical, and from a number of independent areas of linguistic research, including the acquisition of syntax and morphophology, and historical language change—to demonstrate the model's correctness and utility. (Copies available exclusively from MIT Libraries, Rm. 14-0551, Cambridge, MA 02139-4307. Ph. 617-253-5668; Fax 617-253-1690.)