A case refers to the role a noun or a pronoun plays in a particular sentence or clause. There are four main functions and each one can be linked to a specific case in German:
|Case||Function of noun/pronouna||Example|
|Nom.||The noun/pronoun is the subject of the sentence, i.e. the ‘agent’ of what is happening.||Der Schüler kauft einen Computer.‘The pupil buys a computer’.|
|Acc||It is the direct object of a sentence, i.e. the ‘receiver’ of the action.||Die Lehrerin lobt den Schüler
‘The teacher praises the pupil’.
|Dat||It is the indirect object, an additional object to whom/which the action is done.||Er schenkt ihr eine DVD
‘He gives her a DVD’.
|Gen.||It indicates possession or ownership between two nouns.||Das ist das Auto meines Bruders.
‘This is my brother’s car’.
Changes caused by the case system
The various functions and therefore the cases of nouns are usually signalled by the endings of articles and other determiners. When, for instance, a masculine noun is the subject in a sentence and in the nominative, the definite article would be der. If, however a masculine noun acts as the direct object, der must change to den as it is now in the accusative:
Nom. Der Schüler kauft einen Computer.
Acc. Die Lehrerin lobt den Schüler.
Different pronoun forms
Pronouns also have different forms. The personal pronoun er in the nominative changes to ihn in the accusative: Er kauft einen Computer ‘He buys a computer’; Die Lehrerin lobt ihn ‘The teacher praises him’
Other factors that determine the use of cases
Note that apart from the function a noun performs in a sentence or clause, cases can also be ‘triggered’ by two other main factors:
• certain verbs which are linked to one of the cases;
• prepositions which in German require either the accusative, dative or the genitive.