Locality and Evidence Frames as learnability tools for language acquisition

Chomsky (2001b) points out that the properties of grammar must be explained from: (i) primary linguistic data in child language. (ii) an assortment of human perception and memory talents that cooperate in a language acquisition procedure (iii) constraints that derive from quite general neural mechanisms The present paper is concerned with primary linguistic data (i) and their interaction with the acquisition procedure (ii). The initial child data lead to a highly simplified grammar that nevertheless directs the further options of the acquisition procedure. The interaction of the factors (i) and (ii) can be studied by a closer attention to the order of acquisition steps. The relevance of (iii) is less clear. Locality and inclusiveness as general properties of grammatical structures rather seem to provide learnability without revealing much of the neural system as such. The first half of the paper argues that the acquisition procedure starts with a radical reduction of the input data. This results in a sequence of evidence frames. The Single Value Constraint (Clark 1992) and the determined order of acquisition steps are explained when each acquisition step is related to its own evidence frame. The second half of the paper demonstrates how the I(nflection)-marking of predicates and the D(eterminer)-marking of arguments are successive steps. Each invests the marked phrases with properties known as EPP and UTAH. These principles derive from the input. Once acquired, they guide the acquisition procedure to-for example-dummy subjects and agreement, rather than the other way around.