switch-reference

Switch-reference is a form of anaphoric linkage that marks whether the subject of one clause is the same as or different from the subject of another clause it is grammatically linked to. A same-subject marking signals that the two subjects are identical; a different-subject marking signals that they are not. The marking is fully grammaticalized where it occurs, meaning it must be supplied even in contexts where the identity of the subjects is already unambiguous from person marking or from context alone, which is what separates it from an ordinary discourse strategy for tracking reference. Some systems extend beyond a plain two-way contrast, adding a third, underspecified value that leaves the relationship open rather than asserting identity or non-identity, or extending the same logic to relations between subjects and other clausal roles rather than only between two subjects. The phenomenon concentrates heavily in some language families and is close to absent in others, which marks it as a grammaticalization option a grammar takes up rather than a universal requirement.