Split ergativity is shown by languages that have a partly ergative behaviour, but employ another syntax

Syntax

In linguistics, syntax is the study of the principles and rules for constructing phrases and sentences in natural languages....

 or morphology

Morphology (linguistics)

In linguistics, morphology is the identification, analysis and description, in a language, of the structure of morphemes and other linguistic units, such as words, affixes, parts of speech, intonation/stress, or implied context...

 — usually accusative — in some contexts. In fact, most of the so-called ergative languages are not pure but split-ergative.

Split conditions

The split is usually conditioned by one of these:

1. The presence of a discourse participant (a first or second person) in the proposition. The Australian language Dyirbal
   Dyirbal language
   Dyirbal is an Australian Aboriginal language spoken in northeast Queensland by about 5 speakers of the Dyirbal tribe. It is a member of the small Dyirbalic branch of the Pama–Nyungan family...
   
    behaves ergatively in all morphosyntactic contexts, except when one of these is involved. When a first or second person pronoun appears, however, it is marked according to a nominative–accusative pattern (with the least marked case when it is the agent or intransitive, and with the most marked case when it is the patient). This can be explained in terms of the high animacy of a first or second person speaker in the animacy hierarchy.
2. The use of certain tenses
   Grammatical tense
   A tense is a grammatical category that locates a situation in time, to indicate when the situation takes place.Bernard Comrie, Aspect, 1976:6:...
   
    and/or aspect
   Grammatical aspect
   In linguistics, the grammatical aspect of a verb is a grammatical category that defines the temporal flow in a given action, event, or state, from the point of view of the speaker...
   
   s in the verb. The Indo-Iranian
   Indo-Iranian languages
   The Indo-Iranian language group constitutes the easternmost extant branch of the Indo-European family of languages. It consists of three language groups: the Indo-Aryan, Iranian and Nuristani...
   
    family, for example, shows a split between the perfective and the imperfective aspect. A verb in the perfective aspect causes its arguments to be marked using an ergative pattern, while the imperfective aspect triggers accusative marking. (Related languages and others always tend to associate past tense and/or perfect aspect with ergativity.)
3. The type of marking involved. Some languages (including various Austronesian languages
   Austronesian languages
   The Austronesian languages are a language family widely dispersed throughout the islands of Southeast Asia and the Pacific, with a few members spoken on continental Asia that are spoken by about 386 million people. It is on par with Indo-European, Niger-Congo, Afroasiatic and Uralic as one of the...
   
    of New Guinea
   New Guinea
   New Guinea is the world's second largest island, after Greenland, covering a land area of 786,000 km2. Located in the southwest Pacific Ocean, it lies geographically to the east of the Malay Archipelago, with which it is sometimes included as part of a greater Indo-Australian Archipelago...
   
   , such as Sinaugoro) exhibit an ergative–absolutive pattern with respect to case
   Grammatical case
   In grammar, the case of a noun or pronoun is an inflectional form that indicates its grammatical function in a phrase, clause, or sentence. For example, a pronoun may play the role of subject , of direct object , or of possessor...
   
    marking, but a nominative–accusative pattern with respect to agreement
   Agreement (linguistics)
   In languages, agreement or concord is a form of cross-reference between different parts of a sentence or phrase. Agreement happens when a word changes form depending on the other words to which it relates....
   
   .
4. The agentivity of the intransitive subject. In languages like Dakota
   Dakota language
   Dakota is a Siouan language spoken by the Dakota people of the Sioux tribes. Dakota is closely related to and mutually intelligible with the Lakota language.-Dialects:...
   
   , arguments of active verbs such as to run are marked like transitive agents, as in accusative languages, while arguments of inactive verbs such as to stand are marked like transitive objects, as in ergative languages. Languages with this kind of marking are known as split-S languages, and are formally a subtype of active languages.

Examples

An example of split ergativity conditioned by tense and aspect is found in the Hindi

Hindi

Standard Hindi, or more precisely Modern Standard Hindi, also known as Manak Hindi , High Hindi, Nagari Hindi, and Literary Hindi, is a standardized and sanskritized register of the Hindustani language derived from the Khariboli dialect of Delhi...

-Urdu

Urdu

Urdu is a register of the Hindustani language that is identified with Muslims in South Asia. It belongs to the Indo-European family. Urdu is the national language and lingua franca of Pakistan. It is also widely spoken in some regions of India, where it is one of the 22 scheduled languages and an...

 language, which has an ergative case on subjects in the perfective aspect for transitive verbs in the active voice, while in other aspects (habitual, progressive) subjects appear in the nominative case. Example sentences for Hindi

Hindi

Standard Hindi, or more precisely Modern Standard Hindi, also known as Manak Hindi , High Hindi, Nagari Hindi, and Literary Hindi, is a standardized and sanskritized register of the Hindustani language derived from the Khariboli dialect of Delhi...

-Urdu

Urdu

Urdu is a register of the Hindustani language that is identified with Muslims in South Asia. It belongs to the Indo-European family. Urdu is the national language and lingua franca of Pakistan. It is also widely spoken in some regions of India, where it is one of the 22 scheduled languages and an...

are:

लड़का	किताब	ख़रीदता	है
	kitāb	xarīdtā	hai
boy-Msg.NOM	book.Fsg.NOM	buy-IMPERFECTIVE-Msg	be.PRES.3sg

"The boy buys a book."

लड़के-ने	किताब	ख़रीदी
	kitāb	xarīdī
boy.Msg-ERG	book.Fsg.NOM	buy-PERFECTIVE.Fsg

"The boy bought a book."