Nouns are predicates. In Southern Tiwa, nouns occur as serial predicates (‘incorporation’ is serialization). Besides their null pronoun argument, they can also license an argument in the role of possessor (‘Possessor Ascension’ is a superfluous notion). These conclusions emerge from a new morphosyntactic analysis, which also entails that the verb agrees with all and only final terms (multistratal reference is unnecessary). The paradigm gaps, constraints on incorporation, and limited conditions for optional passive, though seemingly intricate, all point to a single hierarchical principle. This hierarchy calls for a simple but previously unexplored formalism, a tiered model reminiscent of autosegmental phonology.