In kadiwéu, a Waikurúan language, the person of the object affects agreement as well as constituent order. The verb must be marked by a relational morpheme if the internal argument is fi rst or second person, and a person agreement morpheme appears according to the 1plOBJ>2>1>3 hierarchy. Moreover, first/second person internal arguments must precede the verb (OV order, the relational is marked) but third person internal arguments follow it (VO order, no relational marker). This work presents the claim that the so-called relational morpheme is an agreement morpheme. According to this view, it is an impoverished morpheme that marks agreement with a dislocated internal argument. More specifi cally, this work claims that kadiwéu person agreement prefi xes are TP agreement, whereas the so-called relational is vP agreement reversed to [-author, -participant]. This work develops Rodrigues's (1990) ideas on person neutralization.30SpecialIssue645658Arregi, K., Nevins, A., (2007) Obliteration vs. Impovireshment in the Basque g-/z- constraint, 13 (1), pp. 1-14. , Penn worling papers in linguistics. PhiladelphiaBonet, E., (1991) Morphology after syntax: Pronominal clitics in Romance, , Tese de doutorado. MIT, Cambridge, MassFreitas, M.L., (2011) Hierarquia de pessoa em ava guarani: considerações a partir da morfologia distribuida, , Unicamp. Dissertação de mestradoGildea, S., Semantic and pragmatic inverse - "inverse alignment" and "inverse voice" - in Carib of Surinam (1994) Voice and Inversion, , GIVóN, T. Amsterdam/Philadelphia: John BenjaminsHalle, M., Distributed Morphology: Impoverishment and Fission (1997) MIT Working Papers in Linguistics 30, pp. 425-439. , Cambridge, MassachusettsHalle, M., Marantz, A., A. Distributed Morphology and the Pieces of Infl ection (1993) The View from Building 20: Essays in Linguistics in Honor of Sylvain Bromberger, , Kenneth HALE & Jay KEYSER (eds.). Cambridge, Massachusetts: MIT PressIto, J., Mester, A., (2003) Japanese Morphophonemics: Markedness and Word Structure, , Linguistic Inquiry Monograph 41. Cambridge, MA: MIT PressJelinek, E., Carnie, A., Argument Hierarchies and the Mapping Principle (2003) Formal Approaches to Function in Grammar, pp. 265-296. , In honor of Eloise Jelinek CARNIE, AHARLEY, HWILLIE, M. (eds.). Philadelphia, PA, USA: John Benjamins Publishing CompanyNevins, A., The Representation of Third Person and its Consequences for Person-Case Effects (2007) Natural Language and Linguistic Theory, 25 (2), pp. 273-313Nevins, A., Sandalo, F., Markedness and morphotactics in Kadiwéu [+participant] agreement (2011) Morphology, 21 (2), pp. 351-378Pollock, J.-Y., Verb Movement, Universal Grammar, and the Structure of IP (1989) Linguistic Inquiry, 20, pp. 365-424Rodrigues, A.D., Morfologia do verbo Tupi (1953) Letras, 1, pp. 121-152Rodrigues, A.D., You and I = neither you nor I: the personal system of Tupinambá (1990) Amazonian Linguistics studies in lowland South American languages, , PAYNE, D. (ed.). Austin: University of Texas PressSandalo, F., Person Hierarchy and inverse voice in Kadiwéu (2009) Liames, 9, pp. 27-40Sandalo, F., Enfraquecimento posicionais e assimetrias em linguas indigenas (2013) Fonologia: teorias e perpectivas, pp. 45-58. , Leda BISOL & Gisela COLLISCHONN (eds.). Porto Alegre: EdipucrsSandalo, F., Freitas, M.L., Uma hipótese morfofonológica para hierarquia de pessoa (2014) Fonologia, Linguística in Focus 10, pp. 37-50. , José S. de MAGALHãES. Uberlândia: EDUFUZwicky, A., On markedness in morphology (1978) Die Sprache, 24 (2), pp. 129-143