The introduction of object symmetry in passives

This paper investigates the introduction of the possibility to promote the indirect object to subject in passives during the second half of the 19th century. An analysis is proposed where the indirect object occupies a position with inherent case throughout the history of Swedish. Before the change, a passive ditransitive verb had no structural case to assign. Thus, the direct object had to move to the subject position, whereas the indirect object remained in its case position. After the change, passive ditransitives have the capacity to assign one structural case. If the direct object receives this case, the indirect object can escape its case position and be promoted to subject. It is also shown that the change was preceded by shifting preferences in the ordering of arguments in the passive voice.