Kasusformen

Kasusformen, or case forms, are the inflectional variants of nouns, pronouns, adjectives, and determiners that encode grammatical relations such as subject, object, possession, and indirect object. They allow a language to signal function without relying solely on word order. Kasusformen arise from declension patterns and may interact with gender and number.

In languages with a robust case system, each noun has different endings for each case. German provides a well-known example: nominative der Mann, genitive des Mannes, dative dem Mann, accusative den Mann; plural nominative die Männer, genitive der Männer, dative den Männern, accusative die Männer. Adjectives and determiners also change form to agree with the noun's case, number, and gender (for instance ein guter Mann vs. eines guten Mannes). Some languages mark case on pronouns as well (ich, mich, mir; du, dich, dir).

Across languages, the set and use of cases vary. Latin uses six cases (nominative, genitive, dative, accusative, ablative, vocative); Russian uses six (nominative, genitive, dative, accusative, instrumental, prepositional); Finnish features a larger system with many cases. Some languages rely heavily on case marking to determine function, while others use fixed word order and prepositions; some employ a mix.

In linguistics and language teaching, Kasusformen are studied as part of declension systems and morphosyntactic alignment, helping explain how meaning is conveyed beyond root lexemes. They remain a central aspect of syntax and morphology in many Indo-European and non-Indo-European languages.