Learn Finnish: Sairas poika menee isoon sairaalaan. - The sick boy is going to the big hospital.

In Finnish, adjectives must match their noun in both number (singular or plural) and case (the word ending). Because the singular noun has the 'into' ending (sairaalaan), the adjective must also be singular and take the matching 'into' ending, becoming isoon.

Are the words sairas and sairaalaan related?

Yes! The word sairas means sick. By adding the place ending -la to the root, Finnish creates sairaala, which literally means a place for the sick, or a hospital.

How do we know the boy is going into the hospital, rather than just to it?

The ending on sairaalaan tells us this. By doubling the last vowel of sairaala and adding -n, we get the 'into' form (called the illative case). The adjective isoon does exactly the same thing: doubles its final -o and adds -n.

Why is menee translated as 'is going' instead of 'goes'?

Finnish does not have a separate continuous tense like English does. The verb menee can mean either 'goes' or 'is going'. You just pick the one that sounds most natural in English based on the context.