Learn Finnish: Paidassa on pieni reikä. - There is a small hole in the shirt.

The basic word for 'shirt' is paita. Adding the 'in' ending -ssa closes the final syllable. This triggers consonant gradation, causing the strong t to change into a weak d.

Why does the sentence start with paidassa instead of a word for 'there is'?

Finnish doesn't have a direct equivalent for 'there is'. Instead, it uses a location-first sentence structure. You put the location first (paidassa), then the verb on (is), and finally the thing that exists there (pieni reikä).

Does the k in reikä undergo consonant gradation here?

Not in this sentence. Consonant gradation happens when you add an ending that closes the syllable. Since reikä (hole) is the subject here, it stays in its basic dictionary form without any endings, so the k remains strong. If you wanted to say 'in the hole', the k would disappear to become reiässä.

Why does paidassa take the -ssa ending instead of -ssä?