German declension is the paradigm that German uses to define all the ways articles, adjectives and sometimes nouns can change their form to reflect their role in the sentence: subject, object, etc. Declension allows speakers to mark a difference between subjects, direct objects, indirect objects and possessives by changing the form of the word—and/or its associated article—instead of indicating this meaning through word order or prepositions (e.g. English, Spanish, French). As a result, German can take a much more fluid approach to word order without the meaning being obscured. In English, a simple sentence must be written in strict word order (ex. A man eats an apple). This sentence cannot be expressed in any other word order than how it is written here without changing the meaning. A translation of the same sentence from German to English would appear rather different (ex. "Ein Mann isst einen Apfel" (a man)-subject eats (an apple)-direct object) and can be expressed with a variety of word order (ex. "Einen Apfel isst ein Mann (an apple)-direct object is eaten by (a man)-subject) with little or no change in meaning.
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As a fusional language, German marks nouns, pronouns, articles, and adjectives to distinguish case, number, and gender. For example, all German adjectives have several different forms. The adjective neu (new), for example, can be written in five different ways (neue, neuer, neues, neuen, neuem) depending on the gender of the noun that it modifies, whether the noun is singular or plural, and the role of the noun in the sentence. English lacks such declinations (except for rare and exceptional ones, such as blond/blonde), meaning that an adjective can be written in only one form.
Modern High German distinguishes between four cases—nominative, accusative, genitive, and dative—and three grammatical genders—feminine, masculine, and neuter. Nouns may also be either singular or plural; in the plural, one declension is used regardless of gender―meaning that plural can be treated as a fourth "gender" for the purposes of declining articles and adjectives. However, the nouns themselves retain several ways of forming plurals which often, but not always, correspond with the word's gender and structure in the singular. For example, many feminine nouns which, in the singular, end in e, like die Reise ("the journey"), form the plural by adding -n: die Reisen ("the journeys"). Many neuter or masculine nouns ending in a consonant, like das Blatt or der Baum ("the leaf" and "the tree") form plurals by a change of vowel and appending -er or -e: die Blätter and die Bäume ("the leaves", "the trees"). Historically, these and several further plural inflections recall the noun declension classes of Proto-Germanic, but in much reduced form.