Caseinflection

Caseinflection, or case inflection, is the morphological process by which nouns, pronouns, and adjectives take different forms to mark grammatical case. Case indicates the syntactic and sometimes semantic relationships of a word within a sentence, such as which word is the subject, the direct object, or the possessor. In languages with case systems, inflection is typically realized through endings attached to the base form, though some languages also use internal vowel changes or separate clitics or words.

Most commonly, case systems include nominative (subject), accusative (direct object), dative (indirect object), genitive (possession), and instrumental or locative cases, among others. The exact set and interpretation of cases vary by language. Case inflection often requires agreement on related words, such as adjectives and determiners, to reflect the noun’s case, number, and gender.

Typologically, languages differ in how they implement case inflection. Fusional languages combine several grammatical features into single affixes; agglutinative languages add clear, separable affixes for each feature; analytic languages rely more on word order and prepositions with little inflection. Notable examples include Latin and Russian (rich case systems), German (four primary cases with article agreement), and Finnish or Hungarian (extensive case inventories).

Historically, many languages have undergone case loss or simplification, especially in the transition from synthetic to analytic structures. Nevertheless, case inflection remains central to the morphology of languages with marked case systems, shaping sentence structure, syntax, and information packaging in communication.