Learn Hardcore Finnish: Sovellus auttaa tarkkailemaan unta.

After verbs like auttaa (“help”), Finnish demands the illative of the first infinitive (often called the 3rd infinitive) to express “to do something.” That illative ending is -maan/-mään, so tarkkailemaan means “(in order) to monitor.”

Why is uni in the partitive case (unta)?

The verb tarkkailla always takes its object in the partitive. Also, the partitive marks ongoing or incomplete actions (“monitoring” sleep over time), so uni → unta.

Can you include a personal pronoun, like minua (“me”)?

Yes. If you want to specify who’s being helped, you say Sovellus auttaa minua tarkkailemaan unta. Finnish often omits the pronoun when it’s clear from context.

What case is sovellus in, and why?

Sovellus is in the nominative case because it’s the subject of the sentence. Subjects in Finnish typically remain in nominative.

How would you make this sentence negative?

Insert ei after the subject and keep the same infinitive form:
Sovellus ei auta tarkkailemaan unta.
(“The app does not help to monitor sleep.”)