How do Nilo-Saharan languages mark grammatical relationships such as subject and object?

In Nilo-Saharan languages, grammatical relationships such as subject and object are primarily expressed through syntactic word order and morphological marking.1

Syntactic Word Order

The positioning of the verb relative to the subject and object varies across the family, often correlating with other syntactic features:
* Verb-initial structures: Many eastern languages, including Nilotic languages, Surmic languages, and the Kuliak and Kadu groups, place the verb before the subject and object.1
* Verb-final structures: Western and northern languages, such as Fur, Kunama, Maban, and Nubian languages, typically place the verb at the end of the sentence.1
* Flexible order: Some languages exhibit relatively free word order, while others, such as those in the Central Sudanic group, alternate between verb-object and auxiliary-object-verb structures.1

Morphological Marking

Beyond word order, these languages frequently use case-marking to define the roles of constituents within a sentence. Syntactic relations are typically expressed through:
* Case-marking suffixes: These are used to indicate various roles, including nominative, absolutive, accusative, genitive, dative, locative, associative, and instrumental cases.1
* Tonal inflection: In some instances, tonal changes serve the same function as suffixes to mark grammatical relationships.1