Learn Hardcore Finnish: Kauppa sulkeutuu aikaisin.

Kauppa means store or shop in English. It’s in the nominative singular form, because it functions as the subject of the sentence. Finnish has no articles, so kauppa can be understood as either a store or the store depending on context.

What is the base form of sulkeutuu, and what does it mean?

The dictionary (infinitive) form is sulkeutua, an intransitive verb meaning to close (by itself). In this sentence, sulkeutuu is the 3rd person singular present tense: it closes.

Why does the verb sulkeutuu end in -uu?

In Finnish, verbs like sulkeutua have a stem ending in -u- and take the 3rd person singular present ending -u. When combined, the two u’s appear as -uu, signaling he/she/it closes.

What does aikaisin mean and what part of speech is it?

Aikaisin is an adverb meaning early. It describes when something happens and does not inflect for case or number. It comes from the adjective aikainen but functions here purely as an adverb.