Learn Croatian: Ostao je dva mjeseca. - He stayed for two months.

After the numbers 2, 3, and 4, Croatian nouns must take the genitive singular form. Mjeseca is the genitive singular of mjesec (month), so we must use it here instead of the standard plural.

Why do we use dva for "two" instead of dvije?

The number two changes based on the gender of the noun it is counting. We use dva for masculine and neuter nouns, and dvije for feminine nouns. Since mjesec is a masculine noun, we use dva.

Where is the word for "he" in this sentence?

Croatian usually drops subject pronouns like on (he) because the verb already gives us that information. The main verb ostao ends in -o, which specifically tells us that a single male person performed the action.

The English translation says "for two months", but there is no word for "for" in the Croatian sentence. Why?

When expressing how long an action lasts (the duration of time), Croatian simply states the amount of time directly. You do not need to add a preposition like "for" in front of it.