Syntactic diversity and language learnability

We propose a preliminary model of a practical parameter setting procedure that aims at bridging the gap between descriptive and explanatory adequacy. We present a list of questions which can successfully set 94 binary parameters in 69 languages drawn from several different families using positive evidence only. Our proposal can be cast within a minimalist model of the language faculty, assuming an underspecified universal grammar and a rich network of implications among parameters. We argue that the workload of parameter setting can be significantly reduced by means of two assumptions: first by positing that only parameters with a positive value are set; second, by showing that parameters can be set exclusively on the basis of a core subset of positive evidence, which we call the Restricted List. We suggest that a model with these properties qualifies as a plausible framework for language acquisition studies, and also lends itself to be applied to closed corpora, such as those available as the sole sources for diachronic studies.