what is it?
German has four highly irregular present-tense verbs — sein (to be), haben (to have), werden (to become), and wissen (to know a fact) — whose forms must be memorised individually. A separate group of otherwise regular verbs undergoes a stem-vowel change in the second-person singular (du) and third-person singular (er/sie/es) only. The three patterns are: e → i (e.g. sprechen → spricht), e → ie (e.g. lesen → liest), and a → ä (e.g. fahren → fährt). All other forms of these verbs are fully regular.
when to use it
sein is used to identify or describe people and things, to state locations, and as the copula linking a subject to an adjective or noun.
haben is used to express possession and to describe states (e.g. Hunger haben, Zeit haben).
werden is used to express becoming or a change of state (e.g. Es wird kalt — It is getting cold).
wissen is used for knowing a fact or piece of information, as opposed to kennen (knowing a person or place).
Stem-changing verbs follow the same rules as regular verbs for meaning and usage; the change is purely a spelling and pronunciation feature that applies whenever the subject is du or er/sie/es.
formation
sein — fully suppletive; every form is unique.
| pronoun | form | meaning |
|---|---|---|
| ich | bin | I am |
| du | bist | you are |
| er/sie/es | ist | he/she/it is |
| wir | sind | we are |
| ihr | seid | you (pl.) are |
| sie/Sie | sind | they/you (formal) are |
haben — the b drops in the du- and er/sie/es-forms.
| pronoun | form | meaning |
|---|---|---|
| ich | habe | I have |
| du | hast | you have |
| er/sie/es | hat | he/she/it has |
| wir | haben | we have |
| ihr | habt | you (pl.) have |
| sie/Sie | haben | they/you (formal) have |
werden — the du-form loses the d, and the er/sie/es-form has a vowel change (e → i) as well.
| pronoun | form | meaning |
|---|---|---|
| ich | werde | I become |
| du | wirst | you become |
| er/sie/es | wird | he/she/it becomes |
| wir | werden | we become |
| ihr | werdet | you (pl.) become |
| sie/Sie | werden | they/you (formal) become |
wissen — the singular forms are irregular; the plural forms are regular.
| pronoun | form | meaning |
|---|---|---|
| ich | weiß | I know |
| du | weißt | you know |
| er/sie/es | weiß | he/she/it knows |
| wir | wissen | we know |
| ihr | wisst | you (pl.) know |
| sie/Sie | wissen | they/you (formal) know |
Stem-changing verbs — the vowel change occurs only in the du- and er/sie/es-forms. All other forms use the plain stem plus the regular endings.
| pronoun | sprechen (e→i) | lesen (e→ie) | fahren (a→ä) |
|---|---|---|---|
| ich | spreche | lese | fahre |
| du | sprichst | liest | fährst |
| er/sie/es | spricht | liest | fährt |
| wir | sprechen | lesen | fahren |
| ihr | sprecht | lest | fahrt |
| sie/Sie | sprechen | lesen | fahren |
The stem change is limited to du and er/sie/es. The ich-form and all plural forms always use the unchanged stem.
examples in context
common pitfalls
Forgetting the stem change in du/er forms. Learners often write *er fahrt or *du sprechst by applying the regular ending to the unchanged stem. The correct forms are er fährt and du sprichst.
Extending the stem change to ich or the plural. The change is restricted to the two singular forms above. *ich fähre and *wir sprichen are both wrong. The correct forms are ich fahre and wir sprechen.
Regularising haben. Applying the standard ending to the full stem gives *du habst, which is incorrect. The b drops: the correct form is du hast.
Regularising wissen. The singular forms of wissen look like a modal verb, not a regular verb. *du wisst and *er wisst are wrong. The correct forms are du weißt and er weiß.