The syntax of eccentric agreement: The Person Case Constraint and Absolutive Displacement in Basque

International audienceThis article explores a syntactic approach to the Person Case Constraint, a ban on 1st/2nd person agreement caused by a dative. The approach proposes that the constraint is due to the interference in person Agree of a head H and its expected controller α by a dative between the two (H > DAT > α, where > is c-command). This predicts that it is absent if the dative does not intervene (α > DAT), or if α moves past the dative (α > DAT > t α). Both predictions are correct. The latter is developed at length from Basque "absolutive displacement" and Icelandic "long raising", which show the predicted repair of the constraint by movement, through anomalous ergative morphology and overt displacement respectively. A further correct consequence is that the constraint is repaired undetectably in the unaccusatives of accusative languages, except when movement past the dative is unavailable. Morphology does not provide the right tools, since it collapses the required structural distinctions, and the saving effect of movement on agreement is unpredicted. Finally, an independent argument is developed to show that the Person Case Constraint is visible to "narrow syntax"