Irregular German verbs: present tense and simple past
Irregular verbs, sometimes called strong verbs, have irregularities in the present tense indicative, the simple past indicative and the past participle. This post looks at the present tense first, then at the simple past.
Indicative means that we are stating facts when using that verb. If you are not already an intermediate learner of German, then this mood is all you will have learned. All other moods can be deduced from the indicative.
A good German dictionary will indicate in the index whether a verb is irregular or not; usually, this is done with an abbreviation or a mark behind the verb. You can then look at the dictionary’s list of irregular verbs. It usually lists the infinitive, the 3rd person present tense, the simple past, sometimes called the imperfect or preterite, and the past participle.
Irregular verbs in the present tense
The 3rd person present is the one to look out for if you would like to conjugate an irregular verb in the present tense. It shows the irregularity in the 3rd person but assumes that the learner knows the same change also occurs in the 2nd person singular: du fährst, er fährt. The 1st person singular almost always retains the stem of the infinitive plus the ending -e; the exceptions are the modal verbs and wissen (ich weiß), which also change their stem in the 1st person singular. In the plural, all verbs retain their stem, apart from sein, which is irregular in most European languages.
Irregular verbs in the simple past
Verbs are sometimes categorised into regular, irregular and mixed verbs. Mixed verbs are irregular verbs but do not change their stem in the present tense. Mixed and irregular verbs always change their stem in the simple past, and your verb list shows this with the 3rd person singular simple past. With irregular verbs in the simple past, unlike in the present tense, the 1st and 3rd person singular are identical: ich fuhr, er fuhr. The 2nd person singular ends in -st, as in the present tense; the plural endings are -en, -t and -en.
The simple past is more often used in written German, whereas the perfect tense dominates in spoken German. There are geographical differences, though: the simple past is still quite often used in spoken German in the north of Germany, whereas the south prefers the perfect. If what you are talking about happened in the past and is still relevant, it is better to use the perfect to point this out.
If you’d like to learn German with a tutor, I teach private German lessons in London and online German lessons.