Learn Finnish: Heidän anoppinsa on kotona. - Their mother-in-law is at home.

Heidän anoppinsa on kotona.

Their mother-in-law is at home.

Breakdown of Heidän anoppinsa on kotona.

Questions & Answers about Heidän anoppinsa on kotona.

Why do we need both heidän and -nsa? Can I just say heidän anoppi?

In standard Finnish, when the owner is in the third person ("his/her" or "their"), you must use both the genitive pronoun (hänen or heidän) and the possessive suffix on the noun (-nsa/-nsä). In casual spoken Finnish, people often drop the suffix and just say heidän anoppi, but standard Finnish strictly requires heidän anoppinsa.

Why is the suffix -nsa instead of -nsä?

This is determined by vowel harmony. The word anoppi contains the back vowels 'a' and 'o' (the 'i' at the end is neutral), so it must take the back-vowel version of the suffix, which is -nsa.

The lesson mentions another third-person suffix, -Vn. Could I use that here instead?

No, you can't use it in this sentence. The -Vn (lengthened vowel + n) suffix can only be attached when a word is in a grammatical case that ends in a short vowel (for example, the inessive case autossa becomes autossaan). Because anoppi is in the basic nominative dictionary form, you are forced to use -nsa.

Since the owners are plural ("their"), why is the verb on (is) instead of ovat (are)?

The verb always agrees with the subject of the sentence, not the owner. The subject here is the mother-in-law (anoppi), which is singular. The word heidän ("their") just describes whose mother-in-law she is, but it doesn't make the actual subject plural.