A tripartite language, also called an ergative–accusative language, is one that treats the agent of a transitive verb, the patient of a transitive verb, and the single argument of an intransitive verb each in different ways. This contrasts with nominative–accusative and ergative–absolutive languages. If the language has morphological case, the arguments are marked in this way:
- the agent of a transitive verb takes the ergative case
- the object of a transitive verb takes the accusative case
- the single argument of an intransitive verb takes the absolutive case
In this Nez Perce intransitive sentence, the absolutive argument has no suffix and the verb carries the third person agreement prefix hi-:
In a transitive sentence with two third person arguments, the agent is marked with -n(i)m, the patient with -ne, and the verb with the third person on third person transitive agreement marker pée-:
The Ainu language of northern Japan also shows tripartite marking in its pronominal prefixes, with the first person Ku= being the ergative form, =an being the absolutive form and =en= being the accusative form. Ainu also shows the passive voice formation typical of nominative-accusative languages and the antipassive of ergative-absolutive languages. Like Nez Percé, the use of both the passive and antipassive is a trait of a tripartite language.
Tripartite languages are rare. Besides Native American Nez Perce, they include the Vakh dialects of the Khanty language, Wangkumara, Semelai, and, in its singular pronouns, Kalaw Lagaw Ya. Yazghulami is tripartite, but only in the past tense. Several constructed languages, especially engineered languages, use a tripartite case system or tripartite adposition system, notably the Na'vi language.
- Rude, Noel. 1986. Topicality, transitivity, and the direct object in Nez Perce. International Journal of American Linguistics 52:124-153.
- Dixon, R.M.W. (1994). Ergativity. Cambridge: Cambridge University Press. p. 40.
- Nez Perce Verb Morphology
- Rude, Noel. 1988. Ergative, passive, and antipassive in Nez Perce. In Passive and Voice, ed. M. Shibatani, 547-560. Amsterdam: John Benjamins
- Kruspe, Nicole. 2004. A Grammar of Semelai. Cambridge University Press.