A tripartite language, also called an ergative–accusative language, is one that treats the subject of an intransitive verb, the subject of a transitive verb, and the object of a transitive verb each in different ways. If the language has morphological case, the arguments are marked in this way:

• the agent of a transitive verb takes the ergative case
  Ergative case
  The ergative case is the grammatical case that identifies the subject of a transitive verb in ergative-absolutive languages.-Characteristics:...
  
  
• the object of a transitive verb takes the accusative case
  Accusative case
  The accusative case of a noun is the grammatical case used to mark the direct object of a transitive verb. The same case is used in many languages for the objects of prepositions...
  
  
• the argument of an intransitive verb takes the intransitive case
  Intransitive case
  The intransitive case is a grammatical case used in some languages to mark the argument of an intransitive verb, but not used with transitive verbs...
  
   ( absolutive case
  Absolutive case
  The absolutive case is the unmarked grammatical case of a core argument of a verb which is used as the citation form of a noun.-In ergative languages:...
  
  )

In Nez Percé

Nez Perce language

Nez Perce , also spelled Nez Percé, is a Sahaptian language related to the several dialects of Sahaptin . The Sahaptian sub-family is one of the branches of the Plateau Penutian family...

, the ergative-case suffix is -nim, the accusative suffix is -ne, and intransitive arguments take no suffix.

Languages lacking case inflections may distinguish these roles with distinct word order.

Tripartite languages are rare. Besides native American Nez Perce, they include the Vakh dialects of the Khanty language

Khanty language

Khanty or Xanty language, also known previously as the Ostyak language, is a language of the Khant peoples. It is spoken in Khanty-Mansi and Yamalo-Nenets Autonomous okrugs, as well as in Aleksandrovsky and Kargosoksky districts of Tomsk Oblast in Russia...

, Wangkumara

Wangkumara (language)

Wangkumara or Wanggumara is an Australian Aboriginal language from the Karnic subgroup of the widespread Pama–Nyungan languages family and is sometimes also classified as a dialect of Ngura...

 and, in its singular pronouns, Kalaw Lagaw Ya, both Australian languages. Several constructed language

Constructed language

A planned or constructed language—known colloquially as a conlang—is a language whose phonology, grammar, and/or vocabulary has been consciously devised by an individual or group, instead of having evolved naturally...

s, especially engineered language

Engineered language

Engineered languages are constructed languages devised to test or prove some hypotheses about how languages work or might work. There are at least three subcategories, philosophical languages , logical languages , and experimental languages...

s, use a tripartite case system or tripartite adposition system, notably Na'vi language

Na'vi language

The Na’vi language is the constructed language of the Na’vi, the sapient humanoid indigenous inhabitants of the fictional moon Pandora in the 2009 film Avatar. It was created by Paul Frommer, a professor at the Marshall School of Business with a doctorate in linguistics...

.