Some irregular verbs change their stem in the present tense. The stem of a verb is the infinitive form without the –en ending:
| Infinitive: fahren | verb stem: fahr- | stem vowel: a |
Typical vowel change in the present:
In the 2nd and 3rd person singular, the stem vowel e changes to ie, for example with "lesen", or to i, as with "sprechen":
| lesen | sprechen | |||||
| Singular | ich | lese | spreche | |||
| du | liest | sprichst | ||||
| er/sie/es | liest | spricht | ||||
| Plural | wir | lesen | sprechen | |||
| ihr | lest | sprecht | ||||
| sie | lesen | sprechen |
The root vowel a changes to ä in the 2nd and 3rd person singular, like with "fahren":
| fahren | ||||
| Singular | ich | fahre | ||
| du | fährst | |||
| er/sie/es | fährt | |||
| Plural | wir | fahren | ||
| ihr | fahrt | |||
| sie | fahren |
More:
In some cases, not only the vowel changes; the whole stem changes. You already know:
| nehmen | ||||
| Singular | ich | nehme | ||
| du | nimmst | |||
| er/sie/es | nimmt | |||
| Plural | wir | nehmen | ||
| ihr | nehmt | |||
| sie | nehmen |