perusinfinitiiviin

Perusinfinitiivi, also called the bare infinitive in Finnish, is the basic non-conjugated form of a verb. It is the form you would typically find in a dictionary and use when the action is described without person, number, or tense. Common examples include syödä (to eat), lukea (to read), kirjoittaa (to write) and olla (to be). The bare infinitive can end in -a/-ä or -da/-dä, and there are irregulars as with all languages.

In everyday Finnish, the perusinfinitiivi is used in a variety of constructions. It often follows auxiliary or modal verbs, as in haluan syödä (I want to eat) or voi auttaa tehdä sen (can help to do it). It also appears in clauses that express general statements or purpose, for example On tärkeää lukea ennen kokeita (It is important to read before exams) and Aion lähteä nyt, jotta voisin nähdä ystäviäni (I intend to leave now to be able to see my friends). The bare infinitive can also serve as the verb that underlies nominalized forms and compound verb phrases.

Related forms include the nominal infinitive, formed with -minen or -misa, which turns the verb into a noun denoting the act itself, as in lukeminen (reading) or kirjoittaminen (writing). These forms are common in sentences that discuss actions as concepts rather than events tied to a subject.

Note: perusinfiniiviin is the illative case of the noun phrase perusinfiniivi in Finnish grammar, used only in linguistic descriptions and not as a verb form in ordinary speech.