Default by intervention: Allomorphy and locality in the Modern Greek verb

Abstract

An often discussed dimension of the locality conditions on allomorphy is visibility: when do the trigger and target of allomorphy ‘see’ each other? An equally important dimension is intervention: when do the trigger and target stop seeing each other? This paper offers two case studies on intervention from Modern Greek verbal morphology. In Greek, Agr is sensitive to the features of Voice, and T is sometimes sensitive to the identity of the root; but in both cases, allomorphy only takes place when all heads intervening between the target and trigger are null. When at least one intervening head is overt, the target retreats to a default realization. I argue that such patterns, whereby intervention leads to the emergence of a default, are readily understandable in theories where adjacency of heads is a necessary condition for allomorphy, and where only null nodes may be transparent.