װיסן

There are 7 core verbs that are in this category. They are very similar to simple verbs, but they are used as auxiliary verbs and have some irregularities in their conjugation. They are:

• מוזן (muzn) - must, to have to
• קענען (knen) - can, to be able to
• וועלן (veln) - to want
• דאַרפֿן (darfn) - to need to
• זאָלן (zoln) - should, ought to
• מעג (meg) - may, to be allowed to
• טאָרן נישט (torn nisht) - must not, to be forbidden to

Present Tense

In the present tense, modal verbs are conjugated by adding specific endings to the verb stem based on the subject pronoun. To get the verb stem, the ending (normally ן) is removed from the infinitive. These are very similar to simple verbs, but the 3rd person singular does not take the ט ending.

Pronoun	Meaning	Ending	Example
איך	I	־	מוזן ← מוז
דו	you (singular)	סט	מוזן ← מוזסט
ער/זי/עס	he/she/it	־	מוזן ← מוז
מיר	we	ן	מוזן ← מוזן
איר	you (plural)	ט	מוזן ← מוזט
זיי	they	ן	מוזן ← מוזן

Past Tense

The past tense for modal, periphrastic, simple, separable-prefix, and reflexive verbs is formed in a similar manner and follows the same rules.

The past tense is formed using the auxiliary verb האָבן (to have) or זיין (to be) followed by the past participle of the main verb.

In most cases, האָבן is used, but זיין is used with verbs that indicate motion or change of state.

The past participle is often formed by adding גע־ at the beginning and ־ט at the end of the verb stem, though there are many exceptions; in general the past participle needs to memorised.

Pronoun	Formation	Example
איך	האָב + past participle	איך האָב געמוזט
דו	האָסט + past participle	דו האָסט געמוזט
ער/זי/עס	האָט + past participle	ער האָט געמוזט
מיר	האָבן + past participle	מיר האָבן געמוזט
איר	האָט + past participle	איר האָט געמוזט
זיי	האָבן + past participle	זיי האָבן געמוזט

Future Tense

The future tense for modal, periphrastic, reflexive, separable-prefix and simple verbs is formed in a similar manner and follows the same rules. It is formed using the auxiliary verb וועלן (will) followed by the infinitive form of the main verb.

Pronoun	Formation	Example
איך	װעל + infinitive	איך וועל מוזן
דו	װעסט + infinitive	דו וועסט מוזן
ער/זי/עס	װעט + infinitive	ער וועט מוזן
מיר	װעלן + infinitive	מיר וועלן מוזן
איר	װעט + infinitive	איר וועט מוזן
זיי	װעלן + infinitive	זיי וועלן מוזן