German Indefinite Pronouns

Indefinite pronouns (unbestimmte Fürwörter) are used when referring to something or someone in general, as opposed to something or someone particular. They are used without another noun, but can refer back to a noun previously mentioned. Some of them do not change based on gender and case, some of them do.

1. “Etwas” and “Nichts” 

The indefinite pronouns “etwas” (somehting) and “nichts” (nothing) do not change based on gender or case. If used as a subject pronoun, they conjugate the verb in the third person singular. “Etwas” and “nichts” are only used for things, but not for people. 

Examples:
Nichts kann passieren. Nothing can happen. 
Ich kann nichts verstehen. I can understand nothing. 

In the first example, ‘nichts’ is the subject of the sentence, so the modal verb “können” is conjugated based on the third person singular. In the second example, “nichts” is the direct object (accusative), but it does not change. 

2. “Man“

The indefinite pronoun “man” (one), is only used in the nominative case, and does not change based on gender. As a subject pronoun, it conjugates the verb based on the third person singular.  Note: do not confuse “man” with “der Mann” (the man). 
In the accusative and dative it changes to “ein-“, and will take the case and gender specific endings of the indefinite article “ein”. 

Examples:
Man kann nichts verstehen. One can understand nothing. 
Ich kann einen/eine/eins sehen. I can see one.
(depending on the gender of the noun it refers to). 
Er bringt einem/einer etwas mit. He brings one something. 
(depending on the gender of the noun it refers to). 

3. “Jemand” and “Niemand“

The indefinite pronouns “jemand” someone” and “niemand”  are only used in singular. They change based on case, but not based on gender. As the subject, they conjugate the verb based on the third person singular. 

Examples:
Jemand kann mich sehen. Someone can see me. (Nominative)
Ich kann jemanden sehen. I can see someone. (Accusative)
Ich bringe niemandem etwas mit. I bring no one something. (Dative)

4. Plural indefinite pronouns 

Some indefinite pronouns can be used in the plural as well. They conjugate the verb in the third person plural form. These are: 

“alle-” (all/everyone/everything), “einige-” (some), “mehrere-” (several),  “manche-” (some) and “viel-” (many)

Some of them can also be used in such a way that they take singular endings, usually when they mean “-thing” (everything, something, etc). When used as “everything/something”, it takes neutral endings. 

Examples: 
Alle können Deutsch sprechen. Everyone can speak German (nominative, plural)
Ich sehe einige. I see some. (accusative, plural)
Er hat mit allem recht. He is right about (with) everything. (dative, singular)

5. “Jede-” 

The indefinite pronoun “jede-” when used in the singular, follows the above declension table. If used in the plural, it changes to “alle”. 

6. Indefinite articles 

Indefinite articles can be used to refer back to something previously mentioned or to indicate something like “one (of those)’. Here we use the indefinite article and its case and gender specific declension table. 

Examples: 
Ein Mann sitzt im Cafe. – Ja, da sitzt einer. 
A man sits in the cafe. Yes, there is one sitting there. 

In this example “einer” refers back to “ein Mann”, which is a masculine, singular noun in the nominative. 

Autos fliegen nicht. – Doch, da fliegt eins! 
Cars don’t fly. Sure, there’s one flying there! 

In this example, “eins” refers to “das Auto”, which is a neutral, singular noun in the nominative.