Stem-changing verbs (also known as strong verbs and irregular verbs) are verbs in German whose stems change when they are conjugated in certain tenses or moods. These changes are especially common in the present tense (3rd person singular and 2nd person singular), and also appear in the simple past and past participle forms.
How Stem Changes Work
Stem-changing verbs modify their vowel stems according to set patterns. The rest of the verb endings follow regular conjugation rules.
- In the present tense (3rd person singular and 2nd person singular), stem vowels may shift (e.g., e → i, e → ie, a → ä).
- In the simple past and past participle, the stem changes are more irregular and must be memorized.
- Stem changes do not occur in the marked plural forms (e.g., wir, ihr, sie).
Common Stem Change Patterns in the Present Tense
The table below shows the most common vowel shifts in singular forms.
| Pattern | Example | Meaning | ich Form | du Form | er/sie/es Form |
|---|---|---|---|---|---|
| e → i | sprechen (to speak) | Ich spreche Englisch. | spreche | sprichst | spricht |
| e → ie | sehen (to see) | Sie sieht einen Film. | sehe | siehst | sieht |
| a → ä | fahren (to drive) | Du fährst nach Berlin. | fahre | fährst | fährt |
| a → ä | laufen (to run) | Er läuft im Park. | laufe | läufst | läuft |
What stem vowel change pattern do the verbs 'fahren' (to drive) and 'laufen' (to run) follow in singular present tense forms?
a → ä
Both 'fahren' and 'laufen' change the stem vowel a to ä in du and er/sie/es forms (du fährst, er läuft).
Conjugation Examples
Here are full conjugation examples for three common stem-changing verbs in the present tense.
sprechen (to speak) — e → i
| Pronoun | German | English |
|---|---|---|
| ich | ich spreche Deutsch | I speak German |
| du | du sprichst Deutsch | you speak German |
| er/sie/es | sie spricht Deutsch | she speaks German |
| wir | wir sprechen Deutsch | we speak German |
| ihr | ihr sprecht Deutsch | you all speak German |
| sie/Sie | sie sprechen Deutsch | they/you speak German |
sehen (to see) — e → ie
| Pronoun | German | English |
|---|---|---|
| ich | ich sehe den Hund | I see the dog |
| du | du siehst den Hund | you see the dog |
| er/sie/es | er sieht den Hund | he sees the dog |
| wir | wir sehen den Hund | we see the dog |
| ihr | ihr seht den Hund | you all see the dog |
| sie/Sie | sie sehen den Hund | they/you see the dog |
fahren (to drive) — a → ä
| Pronoun | German | English |
|---|---|---|
| ich | ich fahre nach Hause | I drive home |
| du | du fährst nach Hause | you drive home |
| er/sie/es | sie fährt nach Hause | she drives home |
| wir | wir fahren nach Hause | we drive home |
| ihr | ihr fahrt nach Hause | you all drive home |
| sie/Sie | sie fahren nach Hause | they/you drive home |
Which verb form correctly fills in the blank: Du ___ den Hund. (du / sehen)
du siehst den Hund
In the 2nd person singular, 'sehen' changes the stem vowel (e → ie) to conjugate as 'du siehst den Hund'.
Summary
- Stem-changing verbs alter their stem vowels in singular forms (du, er/sie/es) in the present tense.
- These changes are predictable and follow common patterns (e → i, e → ie, a → ä).
- Irregular past tense and past participles show different stem changes (e.g., fahren → fuhr, sehen → sah).
- Memorizing common patterns and examples will help you recognize and correctly use stem-changing verbs.
Flashcards (1 of 18)
- Pronoun: ich
- English: I speak German
Last updated: Wed Jun 18, 2025
