The Syntax of the Person Case Constraint Drives Morphological Impoverishment of Clitics

Abstract

Several varieties of Catalan show restrictions on the morphological expression of person and number in combinations of direct and indirect object clitics. When both direct and indirect objects are third person, there is only one morphological marker for third person (3-3-Effects). When both direct and indirect object are third person and plural, only one of them surfaces with plural marking. I call this latter restriction Unique Plural Exponence (UPE). Dialects differ wrt which argument, DO or IO, surfaces with features, but it is consistently the linearly leftmost one that surfaces with person/number features. This is consistent across dialects with different orders of direct and indirect objects, alternations of clitic order within one dialect and under historical change. I develop a syntactic account of these restrictions that relates them to the Person Case Constraint. The absence of morphological realization is attributed to the failure of person/number licensing in the syntax. An analysis is given for the restrictions on person and number in two dialects that differ in the order of direct and indirect objects and accordingly which argument surfaces without person/number features. The consistent lefthand position of the person marked clitic is derived from the syntactic structure.