Many German grammar books and most German teachers will tell you that you simply need to memorise which verbs are regular and which ones are irregular. Yet, while there is no strictly logical rule that would allow you to identify verbs as regular or irregular, there are several rules rules of thumb and some reliable patterns that will make your life easier.
Let’s start with a general definition. Regular verbs, sometimes also called “weak verbs”, keep their original stem, while irregular (or “strong verbs") have a stem change. While the stem in and of itself doesn’t tell you whether the verb is regular or irregular, there are some clues. However, here you face a chicken and the egg situation; for it is true- at least as far as the present tense in German is concerned- that you need to learn the most common irregular verbs in German by heart. Otherwise, you couldn't logically work out which verb is regular and which one is irregular. The good news is, once you do know that a verb is irregular, you can apply the following patterns to figure out how their stem might change.
In the present tense, the most common common patterns are as follows:
e - i
Also werden (used to construct the future tense in German), geben, nehmen, essen, gelten, helfen, vergessen, treffen, sterben.
e - ie
Also sehen, empfehlen, geschehen.
a - ä
Also schlafen, anfangen, fangen einladen, braten, fallen, halten, lassen, raten, tragen, wachsen, wachsen.
Bear in mind that stem changes only happen in the singular and not in the plural, with the only exception being “sein”. As you can see from the above, normally the stem change happens on the second person singular (du) and the third person singular (er/sie/es). Only the modal verbs können, wollen, möchten, dürfen, mögen have a stem change on the first person singular as well.
To learn more about the conjugation of German verbs in the present tense, check out our post on the topic.
To figure out whether German verbs are regular or irregular in the past, there are two rules of thumb. One is to check the conjugation of the verb in the present tense. If there is a stem change in the singular, it is not only an irregular verb in the present tense but often also irregular in the past.
However, there are exceptions, such as the verb “gehen”, which is regular in the present tense but irregular in the past. So my second rule of thumb is to consider the English language. If there is a stem change in English from present to past, it is a strong indication that the verb may be irregular in German as well.
e.g. to go in the present becomes went in the past, so gehen becomes gegangen in the Perfekt and ging in the Präteritum.
Again, there are exceptions, such as
buy- bought - kaufen- gekauft- kaufte
So when both rules of thumb let you down, you have to memorise whether or not the verb is irregular. The good news is that there are only about 200 irregular verbs in the German language, and since many of them can be worked out with the above patterns, there are very few you have to learn by heart.
On our German language blog "Auf Deutsch, bitte!", you will also find posts on the ten most useful verbs in German, reflexive verbs in German and how to use them, separable verbs and when they split, how to express preferences in German, the German future tense, the German perfekt tense. We also have an article on the most common phrases in German , one that explains the difference between language levels a1, a2, b1, , a comparison between online dictionaries like Linguee, dict.cc, dict.leo and Collins, and a review of the apps Duolingo, Memrise, Babbel, Busuu, and Quizlet. So check out our blog.
You might also be interested in my Ultimate Guide to Learning German. Check it out to learn how to learn German fast.
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