Person-based split ergativity in Nez Perce is syntactic

Nez Perce is one among many ergative languages that consistently use nominative case, rather than ergative, for 1st and 2nd person transitive subjects. Two major lines of analysis have been proposed for the synchronic grammar of this type of ergative split. Morphological analyses approach the phenomenon as a case of syncretism between ergative and nominative in 1st and 2nd person; all transitive subjects are assigned an identical syntax. Syntactic analyses posit a featural or structural distinction between 3rd person subjects and 1st and 2nd person subjects, or the clauses containing them. On the basis of modification and coordination patterns, I argue that person-based split ergativity in Nez Perce requires a syntactic analysis. Comparison of the Nez Perce data with recent findings by Legate (2014) reveals variation among languages showing person-based split ergativity: some languages require a morphological analysis, and some (like Nez Perce) require a syntactic analysis. A treatment of the syntactic type of person-based split ergativity is proposed, making use of person-sensitive phrase structure as introduced by Bianchi (2006) and Merchant (2006).