Iterated D-layers and Multiple Case Exponence: The structure and significance of a morphological rarissimum

The paper addresses a typologically unusual instance of Multiple Exponence – some wh-based items in Digor Ossetic, an agglutinative Eastern Iranian language spoken in the Caucasus, exhibit double case marking in the plural. For example, the allative plural of the indefinite ka-dɐr who-indefinite ‘someone’ is kɐ-mɐ-dɐr-tɐ-mɐ who-allative-indefinite-plural-allative. I propose an analysis of this phenomenon in the framework of Distributed Morphology. The key ingredients of the analysis are the presence of two D heads on the spine of such a nominal; and the possibility of last-resort sharing of a case value between these heads. Furthermore, under appropriate conditions, the case exponents associated with the two D heads undergo haplological dissimilation. The rarity of this kind of double case exponence is due to the fact that a number of independent conditions need to be met simultaneously in order for it to obtain.