Breakdown of Ist das der einundzwanzigste Geburtstag von deiner Schwester?
sein
to be
dein
your (informal)
die Schwester
the sister
der Geburtstag
the birthday
von
from, of / by (agent in passive clauses)
einundzwanzigste
twenty-first
Questions & Answers about Ist das der einundzwanzigste Geburtstag von deiner Schwester?
Why does the number end in -ste here?
For numbers from 20 onwards, German ordinal numbers are formed by adding -ste (or -sten) to the base number. Since 21 is einundzwanzig, the 21st is einundzwanzigste. Earlier numbers from 2 to 19 just use -te.
Why does einundzwanzigste end with just an -e instead of -en?
Ordinal numbers follow the exact same ending rules as regular adjectives. Here, Geburtstag (birthday) is a masculine noun acting as the subject of the sentence (nominative case). After the definite article der, the adjective simply takes an -e.
Why is einundzwanzigste written as one giant word?
In German, compound numbers are written together as a single continuous word, no matter how long they get! So the words for "one-and-twentieth" literally mash together into einundzwanzigste.
Why does it say von deiner Schwester instead of von deine Schwester?
The preposition von (which means "of" or "from") always forces the following noun into the dative case. Because Schwester is a feminine noun, the possessive word deine must change to deiner in the dative.
Could I say this without using the word von?
Yes! You could use the genitive case instead to show possession: Ist das der einundzwanzigste Geburtstag deiner Schwester? Using von plus the dative case is just a slightly more casual, everyday way to say "of your sister".
Learn Ist das der einundzwanzigste Geburtstag von deiner Schwester and more in German
All course content and exercises are completely free — no paywalls, no trial periods, no signup needed.
- ✓ Practice with interactive exercises
- ✓ Track your progress with spaced repetition
- ✓Learn at your own pace — completely free