In German, in addition to strong verbs and auxiliaries, there is another category of verbs that cannot be ignored: modal verbs. They are indispensable for speaking German correctly.
These verbs are not verbs like the others. They accompany another verb and affect its primary meaning. There are 6 modal verbs in German and they express different conditions:
|Ability / Permission||dürfen (to be allowed to, may) and können (to be able to, can)|
|Liking / Desire||mögen (to like) and wollen (to want to, to intend to)|
|Necessity / Obligation||müssen (to have to, must, to need to) and sollen (shall, to be supposed to)|
Example Dürfen : Du darfst mit mir gehen / You are allowed to come with me
Example Können : Er kann Deutsch sprechen / He can speak German
These two modal verbs express desire. Nevertheless, they express desire in a more or less strong way.
Example Wollen : Ihr wollt bei uns bleiben / You want to stay with us
Example Mögen : Er mag Tobias / He likes Tobias
Example Sollen : Du sollest Heute gehen / You were supposed to leave today
Example Müssen : Ich muss jetzt gehen / I have to leave now
In the present tense modal verbs are irregular in the first three singular persons. They are regular for all persons in the plural.
The preterite of modal verbs is regular (with regard to endings) but umlauts are omitted. In the perfect and plu-perfect modal verbs are formed with the auxiliary haben accompanied by the past participle of the verbs in question.
Be careful, the past participle of modal verbs is formed differently when the verb is accompanied by another verb or principal verb:
When the modal verb is accompanied by a principal verb, the past participle of the modal verb corresponds to its infinitive form.
When the modal verb is not accompanied by a principal verb then the past participle is formed as for weak irregular verbs (or mixed verbs).
The future tense and the subjunctive I of modal verbs are regular tenses. In the subjunctive II the endings of modal verbs are those of the simple past.