The case of unaccusatives in Classical Portuguese
The single argument of unaccusative verbs has gone from being predominantly postverbal in Classical (16th century) Portuguese to being predominantly preverbal in Modern Portuguese. While Portuguese has no morphological case marking, we find that the position immediately before the verb is becoming more and more reserved for subjects, while arguments in postverbal position are more likely to be objects. This correlates with general tendencies in the organization of information structure in Portuguese, which goes from being primarily a Theme – Rheme language with a T(heme)V(erb)X-structure, where X can be any type of constituent to an (X)S(ubject)V(erb)O(bject) structure. This has implications for the case of the arguments. In a TVX structure, the subject of any type of verb is likely to occur postverbally, since there is only room for one argument before the verb. In Classical Portuguese, there is agreement between the postverbal subject and the verb. The change from TVX to (X)SVO is accompanied by the possibility of postverbal subjects of unaccusatives, passives and reflexives to occur without agreement with the verb, thus not receiving nominative case. In modern popular Portuguese this construction is quite common. These arguments then bear very little resemblance to what we traditionally perceive of as subjects. In the popular language, this type of structure may even include an expletive subject pronoun. The preverbal subjects however show all the normal signs of subjecthood in Portuguese: They occur in the canonical preverbal subject position where they receive nominative case, there is agreement with the verb and no expletives.