Plural Partitive and Genitive

The plural partitive and genitive are built on the i-plural stem: a plural -i- (written -j- between vowels) is added to the word, often changing the vowel before it.

• Partitive plural ends in -a/-ä, -ja/-jä or -ita/-itä: kirjoja, ystäviä, lapsia, ihmisiä, kaupunkeja, omenoita. Use it after paljon, kilo and useita, after negation, and for an indefinite group as subject: Pihalla leikkii lapsia (There are children playing in the yard).
• Genitive plural ends in -en/-jen, -den/-tten or -ten: kirjojen, ystävien, lasten, ihmisten, huoneiden. Use it for 'of the …' and before postpositions: lasten huone (the children's room), ystävien kanssa (with friends).

Both forms use the strong grade: kengät → kenkiä, kenkien.