sein
to be
Sein (to be) is the German verb you will use more than any other, and it is also the most irregular one in the language. Nothing about its forms follows from the infinitive. The present tense runs ich bin, du bist, er ist, wir sind, ihr seid, sie sind, and none of those shapes look like sein itself.
It does two jobs. On its own it links a subject to a description: ich bin müde (I am tired), das ist mein Bruder (that is my brother). As an auxiliary it builds the perfect tense for verbs of motion and change of state: ich bin gegangen (I went), sie ist eingeschlafen (she fell asleep). Most other verbs take haben instead, so knowing which group a verb belongs to matters.
The simple past is war (ich war, du warst, wir waren). Unlike most German verbs, this past tense is normal in conversation, not just in writing. Germans say ich war müde far more often than ich bin müde gewesen.
One thing catches learners out: sein is also the possessive word for "his" or "its". Sein Auto means "his car" and has nothing to do with the verb. The two words are unrelated and only happen to be spelled the same, but context always makes the difference clear.
Useful expressions built on it: es ist mir egal (I don't care), das kann sein (that may be), and sei still (be quiet), which uses the irregular imperative sei.
English
to be
Perfekt
ich bin gewesen
Partizip II
gewesen
Auxiliary
sein appears in the following vocabulary collections:
Ich bin müde.
I am tired.
The verb ‘bin’ is in position 2.
Du bist mein Freund.
You are my friend.
Simple subject–verb order.
Er ist in der Schule.
He is at school.
Place comes after the verb.
- What does sein mean in German?
- Sein means "to be", the verb that links a subject to a description, as in ich bin Student (I am a student). The same spelling is also the possessive word for "his" or "its", as in sein Hund (his dog).
- How do you conjugate sein in the present tense?
- The present tense is ich bin, du bist, er/sie/es ist, wir sind, ihr seid, sie/Sie sind. None of these forms resemble the infinitive, so they have to be memorized as a set.
- Is sein regular or irregular?
- Sein is irregular, and it is the most irregular verb in German. Its present tense, its simple past (war), and its past participle (gewesen) all use different stems.
- What is the past tense of sein?
- The simple past is war: ich war, du warst, er war, wir waren, ihr wart, sie waren. The perfect tense is ich bin gewesen, using sein as its own auxiliary. In speech the simple past war is far more common than the perfect form.
- When do you use sein instead of haben in the perfect tense?
- Use sein for verbs that describe movement from one place to another (gehen, fahren, kommen) and for verbs that describe a change of state (einschlafen, sterben, werden). Everything else takes haben.