Grammatically-based Target-inconsistencies in Child Language

The continuity hypothesis states that early grammars are full-fledged UG-constrained grammatical systems, cast in the same mould as adult grammars and accessible to description and explanation through the same analytic tools. The fundamental validity of this hypothesis is confirmed by the results achieved by theory-guided acquisition studies over the last twenty years (see Guasti 2002 for a detailed synthesis). But the continuity hypothesis must deal with the dynamics of development. The study of development reveals that early productions are not mere structural copies of adult utterances: there are certain systematic discrepancies which call for an explanation. One important task of developmental linguistics is to precisely describe these discrepancies, and the changes they undergo. The analytic tools provided by formal syntax have turned out to be precious in this respect, but we want to go beyond an accurate descriptive chart of development, and try to understand what the inner causes are of the observed developmental course: why does the child entertain partially non-target consistent systems? And what makes her eventually converge to the target system?