German declension

German declension is the paradigm that German uses to define all the ways words can change shape to reflect their role in the sentence: subject, object, etc. Declension allows speakers to mark a difference between subjects, objects, indirect objects and possessives by changing the form of the word—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.

As a fusional language, German marks nouns, pronouns, articles, and adjectives to distinguish case, number, andgender.

Modern High German distinguishes between four cases—nominative, accusative, dative, and genitive—and threegrammatical genders—feminine, masculine, and neuter. Nouns may also be either singular or plural.

Articles

Definite articles

These correspond to the English "the".

Indefinite articles

These correspond to English "a", "an", or "one". Note that there is no plural.

Nouns

Only the following nouns are declined according to case:

• Masculine weak nouns gain an -n (sometimes -en) at the end in cases other than nominative.
• The genitive case of other nouns of masculine or neuter gender is formed by adding -s (sometimes -es).
• Nouns in plural that do not already end in -n or -s (found in loanwords) gain an -n in the dative case.

There is a dative singular marking -e associated with strong masculine or neuter nouns, e.g. der Tod and das Bad, but this is nearly obsolete in contemporary usage, with the exception of fossilized phrases, such as zum Tode verurteilt ("sentenced to death"), or titles of creative works, e.g. Venus im Bade ("Venus In The Bath").

Pronouns

Personal pronouns

Genitive case for pronouns is currently considered archaic  and is used only in certain archaic expressions like "ich bedarf seiner" (I need him)

Interrogative pronouns

1. There is neither a dative nor a genitive of the impersonal interrogative pronoun. Generally, prepositions that need to be followed by either case merge with "was" to form new words such as "wovon" ("whereof") or "weswegen" ("for what reason").

Relative pronouns

Possessive pronouns

All possessive pronouns conform to the same inflectional paradigm:

To illustrate, here is the complete paradigm of mein ("my").

Demonstrative pronouns 

These may be used in place of personal pronouns to provide emphasis, as in the sentence "Den sehe ich" ("I see that"). Also note the word ordering: den corresponds to "that", and ich corresponds to "I". Placing the object at the beginning of the sentence places emphasis on it. English, as a generally non-declined language, does not normally show similar behavior, although it is sometimes possible to place the object at the front of a sentence for similar emphasis, as in: "Him I see, but I don't see John".

Reflexive pronouns

Used when a subject and object are the same, as in "Ich wasche mich" = "I wash myself"

Indefinite pronouns

the pronoun "man"

Attributive adjectives

Predicate adjectives are undeclined. Other adjectives use the following declension patterns.

Strong inflection^[7]

This is used when there is no preceding article.

Weak inflection^[7]

This is used when there is a preceding definite article ("der-word"). These include jen- ("that, those"), solch- ("such a"), manch- ("many, some"), jed- ("each, every"), all- ("all"), dies- ("this, these"), and welch- ("which").

Mixed inflection

The so-called "mixed" endings are not distinct, prescriptive endings but rather descriptive of the language in practice. The gender of a noun must be indicated by some means, and because the masculine and neuter forms of the indefinite article and possessive pronouns are identical, the adjective must indicate the gender of the word. For example, "Ein tolles Auto". Without the adjective ending "es", it would not be clear if "Auto" were a masculine or neuter noun.

Mixed inflection is same as weak inflection, except bold suffixes (masculine nominative, neuter nominative and accusative) that are same as strong inflection.

Non-declining geographic attributive adjectives

Many German locality names have an attributive adjective associated with them which ends in -er, for example Berliner for Berlin andHamburger for Hamburg, which are not marked for case but always end in -er. If the place name ends in -en, like Göttingen, the -er usually replaces the terminal -en.