German/Grammar/Modal auxiliary verbs

Modal auxiliary verbsEdit

In this section we'll cover verbs which combine with the infinitive of other verbs to create a new meaning. We've seen one of these already, werden, which combines with an infinitive to form the future tense.


We introduced auxiliary verbs in the section on the future tense. In addition to forming new tenses, an auxiliary verb can change the meaning in some other way. There are other special forms of of verbs which can be used with auxiliary verbs, for example the verb "to have" combines with the special form "seen" of the verb "to see" to form the perfect tense, a type of past tense: "He has seen." (In this case the special form is called the past participle and we'll be covering the German version in more detail later.) In this section we'll be covering only those verbs which combine with the infinitive of another verb.

A modal verb is an auxiliary verb that changes the modality of a sentence. Modality is used to indicate possibility or desire rather than actual fact. For example "He sees a dog," expresses a simple fact, but "He can see a dog," expresses a possibility; he might not see the dog at the moment but he can if he wants to. In both German and English, modality is usually expressed by combining an auxiliary verb with the infinitive of the main verb.

There are some verbs that might be called auxiliary because they combine with another verbs, but they don't form a new tense or change the modality. English, in most cases, requires the verbs to be connected with a "to":

  • "We decided to buy."

It's also possible that verb can combined with the gerund, formed in English by adding "-ing", of another verb:

  • "We don't encourage smoking."

These are handled differently in German and we'll be covering them in other sections.

The sentence structure with a modal verb is the same as with werden and the future tense. As an example we'll use dürfen, which is similar to "may"; in the first person singular it's darf. Compare:

  • Werde ich dich küssen? – "Will I kiss you?"
  • Darf ich dich küssen? – "May I kiss you?"

In both, the auxiliary verb is conjugated and placed where the finite verb should go, in this case the first position because it's a polar question. And in both cases the main verb is changed to the infinitive and moved to the end of the clause.

The six modal verbs in German are dürfen, können, mögen, müssen, sollen and wollen. This is almost the same list as the past-like present verbs we covered in the section on irregular verbs. The verb "wissen" is absent because it can't be used as a modal verb. Of the rest, we've only covered mögen and wollen in detail there because they have non-modal meanings. We'll also cover lassen here because it's "modal-like", an edge case that should have special treatment.


You use dürfen for permission or to be allowed to do something. It's usual translation is "may". It follows the past-like present conjugation pattern with a vowel change from ü to a in the singular of the present tense. Examples:

  • Darf ich dich küssen? – "May I kiss you?"
  • Wir dürfen die Kekse essen. – "We may eat the cookies."


You use können to express the ability to do something, much like its English cognate "can". It follows the past-like present conjugation pattern with a vowel change from ö to a in the singular of the present tense. Examples:

  • Er kann einen Hund sehen. – "He can see a dog."
  • Wir können in die USA fliegen. – "We can fly to the US."

As with the English "can", können is sometimes used informally to express permission rather than ability.


Recall that mögen as a transitive verb means to like or enjoy something. But when combined with an infinitive it expresses a possibility. This sense is similar to its English cognate "may", though "might" is often a better translation. Confusingly, mögen is not used for permission as "may" is in English; for permission use dürfen. There is a great deal of overlap in meaning between mögen and können here; können is usually preferred and it's unusual to use mögen in this sense. We'll see that mögen gets more use in the subjunctive, but that will be covered in another section. Example:

  • Es mag so sein. – "It might be so."


This is a cognate to the English "must" and usually has about the same meaning, expressing a need or obligation to do something. It's often better to translate this as "have to"; see the section on negation below. It follows the past-like present conjugation pattern with a vowel change from ü to u in the singular of the present tense. Examples:

  • Ich muss gehen. – "I have to go."
  • Wir müssen hier bleiben. – "We must stay here."


This is cognate to both "shall" and "should" in English, but the meaning is closer to "should". This could be a question of morality or it can be a recommended action. It can also mean that something is intended or supposed to happen; in this sense it's a kind of imperative. It can only mean "shall" in the biblical sense, as in "Thou shalt not steal." With such a variety of possibilities, you need to pay attention to context to understand the correct meaning. It follows the past-like present conjugation pattern with no vowel change. Examples:

  • Du solltest deine Mutter anrufen. – "You should call your mother." (Moral issue)
  • Du solltest Gemüse essen. – "You should eat vegetables." (Recommendation)
  • Wir sollen drinnen bleiben. – "We're supposed to stay inside." (Intention)


As we mentioned in the section on irregular verbs, this is a cognate to the English "will" but has a very different meaning. Fortunately, its meaning as a modal verb is nearly the same as its non-modal meaning, to express a desire to do something or for something to happen. This is similar, in both meanings, to the English "want". Examples:

  • Ich will meinem Mann ein Geschenk kaufen. – "I want to buy my husband a gift."
  • Wir wollen ihm nicht schaden. – "We don't want to harm him."


This is a cognate to the English "let" and often means "to allow" or "to give permission". So it's meaning is closely related to dürfen, which is modal, and so it follows that lassen is at least "semimodal". Perhaps "modal-like" or "modal adjacent" would work here as well. There are some differences between this and the six "canonical modal" verbs. First, it's not a past-like present verb like the others, just an ordinary stem-changing verb with the a changing to ä in the second (informal) and third person singular. Second, an additional object, the person or thing that's being "allowed", needs to be included. This will have the accusative case, which means the sentence as whole can have two accusative objects. The one that relates to lassen comes first, and the one relating to the infinitive verb comes later. There are many other meanings for this verb; a dictionary is a better place for most of them. But another one that's relevant here is "to have (someone) do (something)" or "to make (someone) do (something)". Again, with multiple meanings you have to use context to understand what is actually meant. Examples:

  • Lass mich dich küssen. – "Let me kiss you."
  • Er lässt mich sein Haus bauen. – "He's having me build his house."
  • Der Rauch lässt den Alarm schrillen. – "The smoke is setting off the alarm."
    • Literally, "The smoke is causing the alarm to sound (shrilly)."

Infinitive droppingEdit

When the infinitive verb is implied by context and the rest of the sentence, it's not unusual to simply drop it. This often occurs:

  • with a phrase for a location and the verbs gehen and kommen. For example:
    • Wir dürfen ins Haus. – "We're allowed (to go/come) in the house"
    • Du musst weg. – "You have to go."
      • This can also be parsed using the separable verb wegmüssen. Both interpretations use the same words and have the same meaning.
  • with the name of a language and kennen.
    • Ich kann Niederländisch. – "I know Dutch."

Negation with modal auxiliariesEdit

Negation in German works differently from English when it comes to müssen. With the English "must" the negation is applied to the infinite verb. So in "You must not go," the meaning is that "not going" is the only possibility. In German, the negation is applied to the auxiliary verb or the sentence as a whole. So Du musst nicht gehen, means that it's false that "You must go." In other words it means "You don't have to go," rather than "You must not go." This is quite a difference in meaning and it can be quite confusing to English speakers. But the same issue exists with most of the modal auxiliaries to varying degrees, and it's a very good idea to translate the meaning to an English expression involving "to", at least mentally, before attempting to translate the negation. So think of the following more complicated phrases instead of the word for word translation when dealing with negation.

  • dürfen – "to be allowed to"
  • können – "to be able to"
  • müssen – "to have to"
  • wollen – "to want to"

For example:

  • Wir dürfen die Kekse nicht essen. – "We're not allowed to eat the cookies." (Not "We're allowed to not eat the cookies.")
    • This is the way you'd say "We must not eat the cookies."
  • Ich kann es nicht fassen. – "I'm not able to believe it." or "I can't believe it." (Not "I'm able to not believe it.)

It seems sollen is an exception to this; negations involving sollen are applied to the infinitive.


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