What Causes the Alternation of Agentive Verbs in Brazilian Portuguese?

It has been noted that agentive verbs, i.e. verbs that would not be expected to undergo the causative alternation, according to Levin & Rappaport Hovav (1995), participate in a causative-like alternation in Brazilian Portuguese (BP). I call this alternation ‘the agentive alternation’ (AA). In this paper, I argue that the AA is a byproduct of the loss of the clitic se that occupies the position of an external argument in VoiceP (Schäfer 2008). I show that the AA alternation is different from the causative alternation and the verbs that participate in the AA share characteristics with BP unmarked generic middles. Importantly, in spite of the loss of voice morphology, BP unmarked middles project unnacusative syntax. As a result, there is no difference between middles and anticausatives in BP in respect to their transitivity status and verbs previously only licensed in middles were generalized as alternating verbs.