declension

Declension is the system by which certain words, especially nouns, pronouns, and adjectives, take different forms to indicate grammatical function in a sentence. These forms are organized into paradigms, or declensions, that signal case (such as subject or object), number (singular or plural), and, in many languages, gender. Adjectives and determiners commonly agree with the nouns they modify in case, number, and gender, creating concord between words.

In languages with rich case systems, each noun class has its own set of endings. Latin, for example, has several noun declensions with distinct patterns of endings for each case and number. German has multiple declension patterns (strong, weak, and mixed) that affect both nouns and adjectives. Russian and several other Slavic languages use six or more grammatical cases, shaping sentence structure without relying solely on word order. Finnish and other Uralic languages employ extensive case systems with suffixal modifications.

Not all languages use declension to the same extent. English has largely shed noun inflection, retaining limited pronoun case (I vs. me) and some remnants in fixed expressions, while verbs carry more overt inflection. In languages with limited declension, syntax often relies more on word order or prepositions to express grammatical relationships.

Declension is a subset of inflection, the broader process of creating different word forms to express grammatical categories. It is distinct from conjugation, the inflection of verbs, though both contribute to the broader system of grammatical marking in a language.