Modal verbs: kann, muss and will

German has six modal verbs: the ones that sit in front of another verb and colour it, as in I can go, I must go, I want to go. All six are irregular in the same way, so learn them as one block. Then one word-order rule: the other verb goes to the end.

The six

The highlighter marks what changes: the vowel in the singular and the ending.

One warning first. will does not mean will: Ich will gehen is I want to go, not I shall go. German builds its future with werden: Ich werde gehen. - I will go.

They break in the same two places

A normal verb goes ich sage, du sagst, er sagt. The modals all do two things differently:

1. No ending in the ich and er forms. They are identical:

• Ich kann schwimmen. - I can swim.
• Er kann schwimmen. - He can swim.

2. The vowel changes in the singular, and the plural puts it back:

• Ich muss arbeiten. - I have to work.
• Wir müssen arbeiten. - We have to work.

Here are all six in the present. Read down a column: singular vowel, then the infinitive's vowel back in the plural.

sollen never changes its vowel, and wollen swaps o for i, which is where will comes from. There is no ß in muss: after a short vowel German writes ss.

The other verb goes to the end

The modal is conjugated and sits second, like any German verb. The other verb is an infinitive and goes to the very end of the clause, however much comes in between:

• Ich kann heute kommen. - I can come today.
• Er muss nach Hause gehen. - He has to go home.
• Wir wollen das Kind sehen. - We want to see the child.

The two verbs form a bracket around the middle. Three more positions to know:

In a question the modal goes first and the infinitive still waits at the end. After dass, the modal itself joins the end, after the infinitive (German conjunctions has the rule). And a modal may stand alone when the other verb is obvious: Ich kann Deutsch. - I can speak German.