German/Grammar/Irregular verbs

Irregular verbs
Once you eliminate stem-changing verbs, German has surprisingly few verbs that are irregular in the present tense, and we'll increase our our inventory of verbs a bit by introducing many of them here. We'll postpone the rest until we cover a bit more grammar and can use them as they're meant to be used. These include sein ("to be") and werden ("to become"), which will be covered in the next section, and some of the past-like present verbs (defined below).

tun
Traditionally, German textbooks in English tend to postpone introducing this verb long past where should be, given that it is so common. This is understandable since it's a cognate to the English "do", and while it can often be used the same way, it's use in German is much more restricted than it is in English. So, rather than have students using tun inappropriately, textbook authors apparently have chosen to not tell readers about it until they've reached some mastery of other aspects of the language.

It means "to do" in the sense of to perform or carry out an action. As such it often takes an abstract noun as its object. It is not, like the English "do", used with other verbs to form negations, to add emphasis, etc. Even in the sense of performing an action, tun has strong competition from machen – "to make", which can be nearly synonymous with it.

This is the only verb in German that ends with -un, so there is a good reason to call it irregular in the infinitive.

Example: In most cases there is a more specific verb available for a given activity, and tun should only replace it when necessary. So: rather than for "You're working."
 * Du tust deine Arbeit. – "You're doing your job."
 * Du arbeitest.
 * Du tust Arbeit.

haben
The verb for "to have" is often irregular in European languages, and German is no exception. It's not as irregular as one might fear though, at least in the present tense, since it only drops the b in certain cases.

Example:
 * Ich habe einen Hund. – "I have a dog."
 * Note that haben is a transitive verb and uses the accusative case for einen Hund.

Past-like present verbs
The technical term for these is "preterite-present verbs", but this rather jargony expression masks a simple description of what they are. These verbs are conjugated in the present tense similar to the way many verbs are conjugated in the past tense. Since we haven't actually done the past tense yet, think of this as a preview of what conjugating verbs, some of them anyway, in the past tense will look like.

There are only seven of these verbs: dürfen, können, mögen, müssen, sollen, wissen, wollen. We'll need to postpone covering some of them, dürfen, können, müssen, sollen, in detail until later when we talk about modal verbs.

wissen
This verb means "to know", but only in the sense of knowing a fact, or of being aware of something. You would use kennen to to mean "to know" in the sense of being acquainted with a person, or being familiar with something.

Notice there are several differences between the way this verb is conjugated and the stem-changing verbs covered earlier. For one thing, the vowel changes in the first person singular (ich) as well as in the second and third person singular. Also, the endings are dropped in the first person singular (ich) and third person singular (er, sie, es). The vowel change pattern and the dropped endings are features of all the verbs of this type. You may also notice that the ss in the stem changes to ß in certain places, but this is simply a side-effect of the vowel change together with German spelling rules; in Switzerland there is no change, so weiss instead of weiß.

For example:
 * Ich weiß die Antwort. – "I know the answer."
 * Weißt du die Antwort? – "Do you know the answer?"

mögen
This means "to like", though be aware there are many ways to express this sentiment depending on what you like and other circumstances.

For example:
 * Ich mag Schokolade. – "I like chocolate."
 * Magst du Schokolade? – "Do you like chocolate?"

wollen
This means "to want". It's a cognate to the English future tense forming word "will", but it's a false friend; the meanings aren't really the same any more. "To want" was a common meaning of "to will" in English, but it's rare in modern English, surviving mostly in the nouns "will" and "goodwill, and in "willing", "willingly", and the phrase "do what you will".

For example:
 * Ich will Ruhe! – "I want quiet!"
 * Willst du einen Keks? – "Do you want a cookie?"

Modal verbs
In another section we will cover modal verbs, which describes the way certain verbs can be used in a sentence. Aside from wissen – "to know", the past-like present verbs are also known as "modal verbs" because they can be used this way.