Finding "Some" Thing with irgendein-
When you are rummaging through a disorganized, dusty storage unit, you might not be looking for a specific box or a specific book—just any box. By adding the prefix irgend- to the indefinite article ein-, you get irgendein- (some / any).
Because it is built on ein, irgendein- is only used with singular nouns. It declines exactly like ein, matching the gender and case of the noun.
| When I rummaged in the cardboard boxes, I found some old book. | Als ich in den Kartons wühlte, fand ich irgendein altes Buch. |
Notice how dative endings apply when required by a preposition like in (when answering "where?"):
| We have to search in some dusty cardboard box. | Wir müssen in irgendeinem staubigen Karton suchen. |
| We'll search in some old box before we give up. | Wir suchen in irgendeiner alten Kiste, bevor wir aufgeben. |
Plurals with irgendwelch-
Since ein (a/an) doesn't have a plural form, we use irgendwelch- to say "some" or "any" with plural nouns.
It takes standard plural determiner endings: -e in the nominative and accusative (irgendwelche), and -en in the dative (irgendwelchen).
| Have you seen any dusty cardboard boxes? | Hast du irgendwelche staubigen Kartons gesehen? |
| I need some empty cardboard boxes for the stuff. | Ich brauche irgendwelche leeren Kartons für das Zeug. |
Putting It All Together
Whether you are digging through a single, non-specific pile or looking for several non-specific boxes, you now have the tools to describe your search.
| I am rummaging in some dusty pile and searching for some cardboard boxes. | Ich wühle in irgendeinem staubigen Haufen und suche irgendwelche Kartons. |