Learnability Theory and the Acquisition of Syntax

Abstract

It is now relatively uncontroversial that innate principles must be involved in language acquisition, but a crucial issue is the nature of these innate principles, in particular whether they are formulated as constraints on language or constraints on learning, or both (Wexler and Manzini 1987), and whether they are specific to language or can be related to other cognitive domains (O'Grady 1987). That is, are the acquisition mechanisms formulated in terms of linguistic principles, or are they formulated in terms of learning principles which are used to acquire a linguistic system? In either case the system acquired is linguistic, but the principles used to acquire it are not necessarily so, or may be partially so. In this paper I would like to explore a distinction between two theories of language acquisition, one which is based on universal grammar (UG), and one which is based on learnability theory (LT). The theory of universal grammar has been widely examined in both first and second language acquisition, whereas leamability theory is a relatively recent area of study which is being developed both within UG and from other theoretical perspectives (Wexler and Manzini 1987, Pinker 1984, O'Grady 1987, Rumelhart and McClellan 1987). For purposes of clarity, I would like to make a distinction between them as potentially different explanations for the developmental facts of language acquisition.