The Finnish plural is trickier than English "house → houses". There are two different markers: -t in the nominative and -i- in every other case. Let's take it step by step — you can't even say "in the shops" without it.
In short: the nominative plural ending is -t (talo → talot). In other cases, an -i- (or -j- between vowels) goes between the stem and the case ending: taloissa (in the houses). And after a number bigger than 1 you use the singular partitive: kaksi taloa.
Nominative plural: -t
The easy one. Add -t to the stem:
| Singular | Plural | Meaning |
|---|---|---|
| talo | talot | houses |
| kirja | kirjat | books |
| opiskelija | opiskelijat | students |
| ovi | ovet | doors |
This is the subject form: Talot ovat vanhoja (the houses are old). Note the adjective is plural too (vanhoja).
Other cases: the -i- marker
As soon as the word goes into any other case, an -i- replaces -t before the case ending. The pattern is: stem + i + case.
| Case | Singular | Plural |
|---|---|---|
| inessive (in) | talossa | taloissa |
| adessive (on/at) | pöydällä | pöydillä |
| illative (into) | kauppaan | kauppoihin |
Before -i- the stem often changes: a final -a/-ä may become -o-/-e- or drop (kirja → kirjoissa, ovi → ovissa). It's regular, but takes practice.
Partitive plural: -ja / -ita
A very common form — after numbers, under negation, for an indefinite amount:
| Word | Partitive pl. | Example |
|---|---|---|
| talo | taloja | Näen taloja. — I see houses. |
| kirja | kirjoja | Luen kirjoja. — I read books. |
| huone | huoneita | Onko vapaita huoneita? — Are there free rooms? |
Genitive plural: -jen / -iden / -ten
"Of the …" in the plural. There are several endings (word-dependent): talojen (of the houses), kirjojen (of the books), huoneiden (of the rooms), lasten (of the children). You need it before postpositions: talojen välissä (between the houses).
Key exception: singular after numbers
After a number bigger than 1, the noun is NOT plural — it's the singular partitive:
| Finnish | Literally | Meaning |
|---|---|---|
| kaksi taloa | two house-sg. | two houses |
| kolme kirjaa | three book-sg. | three books |
| viisi euroa | five euro-sg. | five euros |
More on this in the article on numbers.
What to learn first
Start with the nominative -t (subjects) and the partitive plural (after numbers, negation). Then the -i- in the local cases. The genitive plural and stem changes come with practice. Don't memorise every ending as a list — learn them on high-frequency words.
The plural is one of those blocks where "the rule is clear but it falls apart in speech". The fastest way to make it automatic is with a teacher: at Hei Study we drill the forms on real phrases — see how long Finnish really takes and begin there.