A nominative-accusative language (or simply accusative language) is one that marks the direct object of transitive verbs distinguishing them from the subject of both transitive and intransitive verbs.

If the language has morphological case, then the direct object is marked with a case conventionally known as "accusative", while the subject is marked with another case called "nominative". If there's no case marking, the language can resort to word order (for example, the subject comes before the verb and the object comes after it, as in English).

Examples

Germanic and Romance languages, as well as the majority of other languages in the world, are nominative-accusative. English has no morphological case distinction between nominative and accusative, except for the pronouns, and it relies solely on word order to differentiate subject and object. The same applies to the Romance languages. German retains case marking, most notably applied to articles.

Consider German:

Der Mann kam. "The man arrived."

Der Mann sah den Jungen. "The man saw the boy."

Der and den both mean "the". The form of the definite article changes according to both the grammatical gender and quantity of the noun it applies to, and also according to the case (accusative or dative) prescribed by a transitive verb for its objects.

The subject of the sentence, Mann, is placed in the nominative case. Der is the nominative singular masculine article.

In the second example sentence, the verb sah (like the majority of German transitive verbs) prescribes the accusative case for its object. Thus, the definite article is changed to den, for a masculine singular word (Jungen) in the accusative case.

Old English had a similar system to German, which gradually disappeared from use. (See Declension in English.)