Evidence from the Uto-Aztecan language Hiaki (Yaqui) shows that the internal structure of the verb phrase is tripartite, made up of (at least) VoiceP, vP and a lexical projection (√P or VP). The interaction of applicative and causative morphology, the existence of two kinds of causatives, and the interaction of passive and verbalizing morphology show that the external-argument introducing projection VoiceP (Kratzer, 1996) must be distinct from the verbalizing head vP (Marantz, 1997), as first proposed by Pylkkänen (2002) and subsequently by Cuervo (2003), Collins (2005), Alexiadou et al. (2006), Merchant (2008) and Harley (2009), among many others. This result stands in opposition to earlier proposals in which a single projection, vP, serves both to verbalize and to introduce the external argument, as in Chomsky (1995), Marantz (1997), and Harley (1995). It also challenges the conclusions of Coon and Preminger (2010), who give explicit arguments for the identity of external-argument-introducing Voice and verbalizing v.