Ergative–absolutive language

Ergative-absolutive languages, sometimes called ergative languages, are languages where the subject of an intransitive verb and the object of a transitive verb behave the same way in a sentence. Both behave differently to the subject of a transitive verb.
In English and other nominative languages, the agent ("doer", "she" in "She walked the dog") of a transitive verb and the subject ("doer", "she" in "She walked") of an intransitive verb are both in the nominative case, and the object ("done-to", "dog" in "She walked the dog") is in the accusative case.
In an ergative language, the agent of a transitive verb is in the ergative case, while the subject of an intransitive verb and the object of a transitive verb are in the absolutive case.
Some examples of ergative-absolutive languages include Basque, Georgian, Mayan, Tibetan, Tagalog and the Kurdish language. 
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:
Accusative English:
Hypothetical ergative English: