Liitvormid

Liitvormid are a category of Estonian verb forms formed by combining a finite form of the auxiliary verb olema (to be) with a non-finite part, usually a past participle or, less commonly, another non-finite form. They function to express tense, aspect and voice that are not carried by a single finite verb form. The most common liitvormid are the perfect and pluperfect constructions, as well as passive forms.

In practice, liitvormid appear when the auxiliary has finite person and number, while the participle conveys the main lexical information. Examples include olen teinud (I have done), olen näinud (I have seen), olin teinud (I had done), and on kirjutatud (has been written). Negation is formed with the negative auxiliary pole or ei, as in pole teinud (has not done) or ei ole tehtud (is not done).

Liitvormid are especially central for marking aspect and voice in Estonian. They allow speakers to refer to past actions with present relevance (perfect) and to express completed actions in the past (pluperfect). Passive voice is often formed as liitvorm by combining olema with a passive participle, for example on kirjutatud (has been written). Not all verbs require or easily participate in liitvorms; many can be expressed with simple finite forms in the present, while liitvormid provide a broader set of temporal and voice distinctions.

Overall, liitvormid are a key part of Estonian verbal morphology, enabling nuanced expression of time, aspect and voice through auxiliary plus participle constructions.