Many of the world's languages track constituents across clauses using switch-reference morphemes. These markers convey information about whether arguments in each clause have the same referent (same subject) or different referents (different subject). Switch-reference morphemes tend to appear attached to a verbal head, although they track arguments in two separate clauses. Additionally, switch-reference morphemes may indicate how the temporal denotation of each clause is ordered with respect to the other. Switch reference has been analyzed in the following three ways: first, as an instance of pronominal coreference, regulated by the principles of Binding Theory; second, as relations between the situations depicted by each proposition; and, third, as a phenomenon driven by agreement relations between clauses.

Obviation morphology classifies nominal arguments in a clause depending on their ranking along scales of person, thematic role, animacy, definiteness, and topichood. For example, proximate marking can indicate a highly ranked argument in the person and the thematic role hierarchy. Obviation is frequently signaled through a complex interaction between two paradigms, the obviation paradigm proper (proximate vs. obviative) and a related voice-marking system (direct or inverse).

Since obviation refers to topichood ranking, it also serves the purpose of tracking referents across clauses, so that proximate marking indicates topic continuity, whereas obviative morphology signals change of topic. Likewise, switch reference may track topic continuity by marking subjects as coreferential (same-subject marking), and topic discontinuity through a different-subject setting. However, obviation can rank arguments clause-internally, whereas switch reference always takes place across clauses. Additionally, the case system and the number of arguments of a verb indirectly determine the type of obviation marking, whereas case and argument structure rarely affect switch-reference systems.