Nominative–accusative

Nominative–accusative languages, or nominative languages have a form of morphosyntactic alignment in which subjects of transitive and intransitive verbs are distinguished from objects of transitive verbs by word order, case-marking, and/or verb agreement.

Nominative–accusative alignment can be realized through morphology, by visible coding properties, and/or syntax, by behavioral properties during participation in specific constructions. That type of alignment has a broad global distribution and is one of the major alignment systems characterizing a critical portion of the world’s languages.

A transitive verb is associated with two noun phrases (or arguments): a subject and a direct object. An intransitive verb is associated with only one argument, a subject.

Nominative–accusative alignment uses the same coding system for subjects of transitive and intransitive verbs and a different coding system for direct objects of transitive verbs. The different kinds of arguments are represented as A, S, and O. A is the subject (or most agent-like) argument of a transitive verb, O is the direct object (or most patient-like) argument of a transitive verb, and S is the sole argument of an intransitive verb.

Nominative–accusative languages contrast with ergative–absolutive languages, which use an alignment system that codes subjects of transitive verbs differently from subjects of intransitive verbs and objects of transitive verbs. In an ergative–absolutive system, A is coded as ergative while S and O are coded as absolutive.

It is common for languages (such as Dyirbal and Standard Hindi) to have overlapping alignment systems, which exhibit both nominative–accusative and ergative–absolutive coding, a phenomenon called split ergativity. In fact, there are relatively few languages that exhibit only ergative–absolutive alignment (called pure ergativity) and tend to be isolated in certain regions of the world, such as the Caucasus, parts of North America and Mesoamerica, the Tibetan Plateau, and Australia. Such languages include Sumerian, Standard Tibetan, and Mayan.

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