ergative

Ergative refers to a grammatical alignment in which the subject of a transitive sentence is marked differently from the subject of an intransitive sentence, and the object of a transitive sentence is treated similarly to the subject of an intransitive sentence. This system is called ergative–absolutive alignment.

Under ergative–absolutive alignment, the core distinction is between ergative case marking on the agent of a transitive verb and absolutive marking on the subject of an intransitive verb and the object of a transitive verb. In contrast, nominative–accusative languages mark both the subject of intransitive and the subject of transitive sentences the same (nominative), and the object differently (accusative).

Some languages display split ergativity, where ergative alignment occurs in certain tenses, moods, or grammatical aspects but not others. Others morphologically encode ergativity in the verb through agreement or particle marking rather than on nouns.

Examples of languages with ergative alignment include Basque, Georgian, and many Inuit languages. Several Mayan languages and some Caucasian languages also show ergative structures. The study of ergativity is a central topic in linguistic typology and syntax, helping linguists understand how languages encode the roles of subjects and objects in sentences.