Case in Tiers

This paper presents a theory of surface case which bears a strong formal similarity to autosegmental theory in phonology and morphology. We suggest that surface case forms a tier which is autonomous of phrase structure-and which is associated with NP's of the PS tier by general principles analogous to those which associate tones with segments, or phonemic melodies with CV skeleta. We show that this theory permits parameterization of a variety of case systems, and thus provides some insight into how case might be characterized in Universal Grammar. The theory permits, most strikingly, a unification of Accusative and Ergative systems under one simple parameter, and explanation of the mysterious appearance of postverbal nominative case in the passives of certain Icelandic ditransitive verbs.