Learning datives: The Tolerance Principle in monolingual and bilingual acquisition

We study the learnability problem concerning the dative alternations in English (Baker, 1979; Pinker, 1989). We consider how first language learners productively apply the double-object and to-dative constructions (give the book to library/give the library the book), while excluding negative exceptions (donate the book to the library/*donate the library the book). Our solution for first language acquisition is based on The Tolerance Principle, a formal model that detects productivity from the distributional properties of the input data (Yang, 2005, 2016). This principle predicts an acquisition stage where the constructions are productive, followed by a stage where learners retreat from overgeneralization and form more finely grained rules. This work calls for a formally rigorous model of acquisition, which can incorporate input effects and retain the benefits of an abstract generative grammar without resorting to piecemeal learning. We provide an analysis of child-directed speech in the CHILDES database to support the learning proposal for first language acquisition, while considering its potential applicability to second language (L2) acquisition and first language (L1) attrition.