Ergative–absolutive alignment

In linguistic typology, ergative–absolutive alignment is a type of morphosyntactic alignment in which the subject of an intransitive verb behaves like the object of a transitive verb, and differently from the subject of a transitive verb. Examples include Basque, Georgian, Mayan, Tibetan, Sumerian, and certain Indo-European languages. It has also been attributed to the Semitic modern Aramaic languages. Ergative languages are classified into two groups: those that are morphologically ergative but syntactically behave as accusative and those that, on top of being ergative morphologically, also show ergativity in syntax. Languages that belong to the former group are more numerous than those to the latter.
The ergative-absolutive alignment is in contrast to nominative–accusative alignment, which is observed in English and most other Indo-European languages, where the single argument of an intransitive verb behaves grammatically like the agent of a transitive verb but different from the object of a transitive verb. When ergative–absolutive alignment is coded by grammatical case, the case used for the single argument of an intransitive verb and the object of a transitive verb is the absolutive, and the case used for the agent of a transitive verb is the ergative. In nominative-accusative languages, the case for the single argument of an intransitive verb and the agent of a transitive verb is the nominative, while the case for the direct object of a transitive verb is the accusative.
Many languages have ergative–absolutive alignment only in some parts of their grammar, but nominative-accusative alignment in other parts. This is known as split ergativity.

Ergative vs. accusative languages

An ergative language maintains a syntactic or morphological equivalence for the object of a transitive verb and the single core argument of an intransitive verb, while treating the agent of a transitive verb differently. Such languages are said to operate with S/O syntactic pivot.
This contrasts with nominative–accusative languages such as English, where the single argument of an intransitive verb and the agent of a transitive verb are treated alike and kept distinct from the object of a transitive verb. Such languages are said to operate with S/A pivot.
These different arguments are usually symbolized as follows:

A = agent of transitive verb
O = object of transitive verb, also symbolized as P for "patient"
S = core argument of intransitive verb

The relationship between ergative and accusative systems can be schematically represented as the following:

	Ergative–absolutive	Nominative–accusative
A	ERG	NOM
O	ABS	ACC
S	ABS	NOM

See morphosyntactic alignment for a more technical explanation and a comparison with nominative–accusative languages.
The word subject, as it is typically defined in grammars of nominative–accusative languages, has a different application when referring to ergative–absolutive languages, or when discussing morphosyntactic alignment in general.
Ergative languages tend to be either verb-final or verb-initial; there are few, if any, ergative SVO languages.

Realization of ergativity

Ergativity can be found in both morphological and syntactic behavior.

Morphological ergativity

If the language has morphological case, then the verb arguments are marked thus:

The agent of a transitive verb is marked as ergative case, or as a similar case such as oblique.
The core argument of an intransitive verb and the object of a transitive verb are both marked with absolutive case.

If there is no case marking, ergativity can be marked through other means, such as in verbal morphology. For instance, Abkhaz and most Mayan languages have no morphological ergative case, but they have a verbal agreement structure that is ergative. In languages with ergative–absolutive agreement systems, the absolutive form is usually the most unmarked form of a word.

Basque

The following examples from Basque demonstrate an ergative–absolutive case marking system:
Here -Ø represents a zero morpheme, as the absolutive case is unmarked in Basque with proper nouns. The forms for the ergative are -k after a vowel, and -ek after a consonant. It is a further rule in Basque grammar that in most cases a noun phrase must be closed by a determiner. The default determiner is -a in the singular and -ak in the plural, the plural being marked only on the determiner and never the noun. For common nouns, this default determiner is fused with the ergative case marker. Thus one obtains the following forms for gizon : gizon-a, gizon-ak, gizon-ak, gizon-ek. When fused with the article, the absolutive plural is homophonous with the ergative singular. See Basque grammar for details.

Circassian

Japanese

In contrast, Japanese is a nominative–accusative language:
In this language, the argument of the intransitive and agent of the transitive sentence are marked with the same nominative case particle ga, while the object of the transitive sentence is marked with the accusative case o.

Conlang English

If one sets: A = agent of a transitive verb; S = argument of an intransitive verb; O = object of a transitive verb, then we can contrast normal nominative–accusative English with a hypothetical ergative English:

Georgian

A number of languages have both ergative and accusative morphology. A typical example is a language that has nominative-accusative marking on verbs and ergative–absolutive case marking on nouns.
Georgian has an ergative alignment, but the agent is only marked with the ergative case in the perfective aspect. Compare:
is the root of the word "man". In the first sentence the agent is in the nominative case. In the second sentence, which shows ergative alignment, the root is marked with the ergative suffix.
However, there are some intransitive verbs in Georgian that behave like transitive verbs, and therefore employ the ergative case in the past tense. Consider:
Although the verb "sneeze" is clearly intransitive, it is conjugated like a transitive verb. In Georgian there are a few verbs like these, and there has not been a clear-cut explanation as to why these verbs have evolved this way. One explanation is that verbs such as "sneeze" used to have a direct object and over time lost these objects, yet kept their transitive behavior.

Differing noun-pronoun alignment

In rare cases, such as the Australian Aboriginal language Nhanda, different nominal elements may follow a different case-alignment template. In Nhanda, common nouns have ergative-absolutive alignment—like in most Australian languages—but most pronouns instead follow a nominative-accusative template. In Nhanda, the absolutive case has a null suffix while ergative case is marked with some allomorph of the suffixes -nggu or -lu. See the common noun paradigm at play below:
Intransitive Subject
Transitive Subject-Object
Compare the above examples with the case marking of pronouns in Nhanda below, wherein all subjects are marked the same for case while transitive objects take the accusative suffix -nha.
Intransitive Pronoun Subject
'''Transitive Pronoun Subject-Object '''

Syntactic ergativity

Ergativity may be manifested through syntax, such as saying "Arrived I" for "I arrived", in addition to morphology. Syntactic ergativity is quite rare, and while all languages that exhibit it also feature morphological ergativity, few morphologically ergative languages have ergative syntax. As with morphology, syntactic ergativity can be placed on a continuum, whereby certain syntactic operations may pattern accusatively and others ergatively. The degree of syntactic ergativity is then dependent on the number of syntactic operations that treat the subject like the object. Syntactic ergativity is also referred to as inter-clausal ergativity, as it typically appears in the relation of two clauses.
Syntactic ergativity may appear in:

Word order
Syntactic pivots
Relative clauses – determining which arguments are available for relativization
Subordination
Switch reference
Example

Example of syntactic ergativity in the "conjunction reduction" construction in Dyirbal in contrast with English conjunction reduction.
English :

Father returned.
Father saw mother.
Mother saw father.
Father returned and father saw mother.
Father returned and ____ saw mother.
Father returned and mother saw father.
* Father returned and mother saw ____.

Dyirbal :

Ŋuma banagan^yu.
Yabu ŋumaŋgu buṛan.
Ŋuma yabuŋgu buṛan.
Ŋuma banagan^yu, yabu ŋumaŋgu buṛan. returned, mother father-ŋgu
* Ŋuma banagan^yu, yabu ____ buṛan. returned, mother ____
Ŋuma banagan^yu, ŋuma yabuŋgu buṛan. returned, father
Ŋuma banagan^yu, ____ yabuŋgu buṛan. returned, ____

Crucially, the fifth sentence has an S/A pivot and thus is ill-formed in Dyirbal ; on the other hand, the seventh sentence has an S/O pivot and thus is ill-formed in English.