When you have too many features: Auxiliaries, agreement and clitics in Italian varieties

Syntactic variation can be ascribed to a range of factors. The Borer-Chomsky conjecture, as Mark Baker (2008) refers to it, states for instance that all parameters of variation are attributable to differences in the features of particular items (e.g. functional heads) in the lexicon. In this paper, this hypothesis is carefully considered in relation to a group of Abruzzese dialects that exhibit three seemingly unrelated syntactic patterns: split auxiliary selection, split differential object marking, and omnivorous participial agreement in number/argumental agreement mismatch marking. It will be proposed that these three patterns are closely interrelated, and can be attributed to the presence of an unvalued bundle of φ-features (π). Depending on which XP this head is merged with, different agreement patterns will emerge. Furthermore, these dialects will be shown to differ from another macrogroup of northern Italian dialects purely in the locus of Merge of this extra functional head: it will also be shown that the almost perfect areal complementary distribution between languages with subject clitics and languages with person-driven auxiliary selection is not accidental, but is the result of the presence of an extra φ-probe doubling the features of the subject in different parts of the syntactic spine. A microtypology of 'v 'will be presented, unifying many phenomena that were previously considered unrelated, such as auxiliary selection, participial agreement, differential object marking and subject clitics