Syntacticized topics in Kurmuk: A ternary voice-like system in Nilotic

This article argues that Kurmuk, a little-described Western Nilotic language, is characterized by a syntacticized topic whose grammatical relation is variable. In this language, declarative clauses have as topic an obligatory preverbal NP which is either a subject, an object, or an adjunct. The grammatical relation of the topic is expressed by a voice-like inflection of the verb, called orientation here. While subject-orientation is morphologically unmarked, object-oriented and adjunct-oriented verbs are marked by a subject suffix or by a suffix indicating that the topic is not subject, and adjunct-orientation differs from object-orientation by a marked tone pattern. Topic choice largely reflects information structure by indicating topic continuity. The topic also plays a crucial role in relative clauses and in clauses with contrastive constituent focus, in that objects and adjuncts can only be relativized or contrastively focalized if they are coded as topics. Moreover, some types of adverbial clauses require adjunct-orientation.