Modal Verbs

The most important uses of modal verbs are the communication of obligation, permission and ability. They are used in a very similar way in Polish and English, where in both languages we use a second verb in the infinitive to form a sentence. Note that these modal verbs have no perfective aspect.

Let’s look at each use in turn:


Starting now with the most complicated – powinien, which means should or ought. Powinien is known as a defective verb as it does not conjugate and is not used in quite the same way as most verbs. The English verb ought is also defective and neither ought nor powinien have an infinitive form, i.e. there is no ‘to ought‘.

This is how powinien is conjugated in the present and past tense:
Following this with the infinitive, we can make sentences such as:

Czy kot powinien pić mleko? (Should a cat drink milk?)
Powinieneś był to kupić (You should have bought that)

For a stronger sense of obligation, Musieć fills in for the English verbs must, have to and need to. Note the switch from a to e in the stem of the male person plural forms in the past tense:
Again, follow this with the infinitive:

Muszę tańczyć (I must dance)
Musieliśmy szukać pomocy (We had to search for help)

But be careful when negating musieć – nie muszę means don’t have to (there is no obligation) and it does not mean mustn’t:

Nie muszę się uczyć polskiego (I don’t have to learn Polish)


The verb móc is used to indicate permission – whether you can or mustn’t do something.
Nie możecie tu być (You can’t/mustn’t be here)
Czy mogę palić? (Can I smoke?)


Note the subtle difference between móc and umieć – whilst in English we use the verb can for both permission (I can smoke here) and ability requiring knowledge (I can play the guitar), in Polish there is a distinction. For the latter, use umieć:
Czy dinozaury umiały pływać? (Could dinosaurs swim?)
nie umiem dobrze gotować (I can’t cook well)



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