But first let’s go back and review what a stem is. The stem of a verb is the part of the verb that is left once you take away the –en or – n ending. In regular verbs the stem does not change no matter what ending you add on to it.
Stem changes will become familiar to you over time, as many German verbs are “stem changing”. In most cases only the “you” and “he, she, it” form changes, but it wouldn’t be German if there weren’t exceptions. Let’s have a look at the most common German irregular verbs.
Resources for further reading:
Here is the pronunciation of sein, the most common German irregular verb.
- ich bin - I am
- du bist - you are (informal)
- er/sie/es ist - he/she/it is
- wir sind - we are
- ihr seid - you are (plural)
- sie sind - they are
- Sie sind - you are (formal)

Pronouncing German Irregular Verbs
The three most common German irregular verbs are, without any doubt, sein (to be), haben (to have) and werden (to become). Let's see how they are conjugated in the present tense. Since these are all irregular verbs, their stems cannot be deduced from the base verb, as it happens with regular verbs.
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If you pay close attention to the plural conjugations of haben and werden, you will see these are regular conjugations that attach the correct ending to the verb stem (hab-, werd-). This is a trick: in most cases, the plural subject pronouns conjugations in verbs that are marked as irregular behave like those in regular verbs in the present tense! Sein, to be, is obviously a rare exception.
Now, in the present tense of other irregular verbs, some stems can undergo a vowel change from e to i. We can see this behavior in werden, but also in verbs like geben (to give) and helfen (to help). Other verbs change the e into ie, like lesen (to read), and others take on an umlaut, a two dots sign that is placed over the stem vowel, like fahren (to go, to travel). These changes can be found in the second and third person singular.
Essentially, the stem can change in the following ways:
- e > i
- e > ie
- a/o/u > ä/ö/ü
Now let's see the conjugation of fahren. We will then see a few example sentences featuring these verbs, and others.
What verbs are irregular and what verbs aren't? You cannot tell unless you look the word up in a dictionary, but English may come to the rescue. Many German irregular verbs, in fact, have irregular conjugations in English as well. Think about the verbs we've covered in this lesson: to think, to read, to bring, to go, to speak, to become... these are all irregular English verbs!
Here are a few recommended German lessons to try next!
- Understanding the German nominative.
- If you want to name a place or person in German, then this German nouns lesson is for you.
- German pronouns are a must-know. Get started here.
Bis bald!
Paul Weber: Rocket German