A binary inflectional voice contrast in Mabaan (Western Nilotic)

In Mabaan, a Western Nilotic language, there is a binary inflectional voice contrast in the morphology of verbs. In addition to a morphologically unmarked basic voice, there is a fully productive applicative voice, which is morphologically marked. This applicative voice may be called circumstantial in order to distinguish it from another applicative voice, which is derivational, namely benefactive. The circumstantial voice turns an adjunct into an object, making an intransitive verb transitive and a transitive verb ditransitive. In a main clause, however, a transitive verb needs to be detransitivized via antipassive derivation in order for an adjunct to become object through the circumstantial voice. In some types of subordinate clauses, by contrast, any verb can get the circumstantial voice, whatever its transitivity, derivational status and meaning. This voice is obligatory in relative clauses when the relativized constituent is an adjunct and in some types of adverbial clauses.