kotitehtävänsä
Kotitehtävänsä is a Finnish noun phrase meaning “one’s homework,” formed from kotitehtävä (homework) with the third‑person possessive suffix. The possessive suffix is written as -nsä or -nsa, depending on vowel harmony, yielding forms such as kotitehtävänsä. In practice, the exact suffix varies with the possessor and the surrounding phonology, but kotitehtävänsä is the standard form used for his/her/their homework in contexts where the possessor is clear.
The phrase is normally used to refer to homework owned by a third person, for example Hänen
Usage and interpretation are driven by context. Without an explicit subject pronoun, kotitehtävänsä can be ambiguous