When an English speaker learns that "in the house" is talossa, the instinct is to file -ssa away as the ending for "in" and bolt it onto every word. Finnish will not let you. The very same case, attached to kylä (village), comes out kylässä — not kylässa. This is vowel harmony acting inside a suffix: many Finnish endings exist in two shapes, a back-vowel shape and a front-vowel shape, and the word you attach them to decides which one you use. The good news is that the choice is completely automatic once you can read a stem's harmony class, and that a useful minority of endings have only one shape and never trouble you at all.
The two-shape endings
Here are the common case endings that alternate. Notice that only the vowel changes — the consonants (ss, st, ll, lt, n) are identical in both columns. Back stem talo sits beside front stem kylä, with the neutral-only stem tie (road) in the third column to show that a word built purely from neutral vowels behaves as front.
| Case | Ending | Back: talo | Front: kylä | Neutral-only: tie |
|---|---|---|---|---|
| Inessive ("in") | -ssa / -ssä | talossa | kylässä | tiessä |
| Elative ("out of") | -sta / -stä | talosta | kylästä | tiestä |
| Adessive ("on / at") | -lla / -llä | talolla | kylällä | tiellä |
| Ablative ("off / from") | -lta / -ltä | talolta | kylältä | tieltä |
| Essive ("as") | -na / -nä | talona | kylänä | tienä |
| Partitive | -a / -ä | taloa | kylää | tietä |
The pattern is a single fact repeated six times: a back stem takes the a shape, a front stem takes the ä shape. You do not memorise this per case — you learn it once and it applies to every alternating ending in the language.
Asun pienessä kylässä Lapissa.
I live in a small village in Lapland.
Talossa on kylmä, laita takki päälle.
It's cold in the house, put a jacket on.
Otin kirjan pöydältä ja panin sen laukkuun.
I took the book off the table and put it in the bag.
Note in the last example that pöytä (table) is a front word — it has ö and ä — so the ablative comes out pöydältä (front -ltä), while its consonant t softens to d through gradation. Harmony picks the vowel, gradation shapes the consonant, and the two work independently.
Front words and neutral-only words both take the ä-shape
Two kinds of word take the front ä-shape ending, and it helps to keep them straight:
- Front words proper contain a genuine front vowel — ä, ö, or y. Kylä (has ä), pöytä (has ö), käsi (hand, has ä): all front, all take -ssä, -llä, -ä. So käsi gives kädessä, kädellä, kättä.
- Neutral-only words contain no back vowel and no front vowel — only the neutrals e and i. Finnish resolves these toward the front as well. Meri (sea), vesi (water), tie (road): all take the ä-shape.
Sormus putosi kädestä suoraan lumeen.
The ring fell off my hand straight into the snow.
Meressä ui tähän aikaan vuodesta paljon kaloja.
At this time of year a lot of fish swim in the sea.
Kala ui hitaasti kirkkaassa vedessä.
The fish swims slowly in the clear water.
The endings that never change
Not every suffix has two shapes, and this is genuinely good news: it means there are endings you can attach on autopilot without thinking about harmony at all. Two of the most frequent are completely invariant:
| Case | Ending | Back: talo | Front: kylä | Neutral-only: tie |
|---|---|---|---|---|
| Genitive ("of / 's") | -n | talon | kylän | tien |
| Translative ("into / becoming") | -ksi | taloksi | kyläksi | tieksi |
The genitive -n has no vowel to harmonise, so of course it cannot change. The translative -ksi is the interesting one: it does contain a vowel (i), but i is neutral and has no back partner, so the ending is frozen as -ksi for every word in the language — taloksi, kyläksi, jääksi alike. Learners who over-apply harmony sometimes invent a form like kyläksä; it does not exist.
Talon katto vuotaa taas, pitää soittaa korjaajalle.
The roof of the house is leaking again, I need to call a repairman.
Vesi jäätyi yön aikana jääksi.
The water froze into ice during the night.
Hän opiskelee lääkäriksi Helsingin yliopistossa.
She is studying to become a doctor at the University of Helsinki.
Only the vowel flips — never the consonant
A subtle trap: harmony changes just the vowel of the ending. The consonants stay put. There is no such thing as kyläshä or taloshsa — the inessive is -ssa/-ssä, so kylä + -ssä is simply kylässä, with the ss untouched. Think of the two shapes as the same ending wearing different vowels, not as two different endings.
Missä sä oot? Mä oon vielä koulussa.
Where are you? I'm still at school.
That last example is everyday spoken Finnish (informal / puhekieli): sä oot for standard sinä olet "you are", and oon for olen "I am". The case ending itself, koulussa ("at school", back word koulu), is identical in every register — harmony does not shift between formal and casual speech.
Common Mistakes
❌ Asun pienessä kylässa.
Incorrect — a front stem needs the front vowel.
✅ Asun pienessä kylässä.
I live in a small village.
❌ Sormus putosi kädessa.
Incorrect — käsi is a front word (it has ä), so the ending is front.
✅ Sormus putosi kädessä.
The ring fell off my hand.
❌ Vesi jäätyi jääksä.
Incorrect — the translative -ksi never harmonises.
✅ Vesi jäätyi jääksi.
The water froze into ice. (-ksi is invariant)
❌ Kissa nukkuu talossä.
Incorrect — a back stem keeps the back vowel.
✅ Kissa nukkuu talossa.
The cat is sleeping in the house.
❌ Ota kirja pöytältä.
Incorrect — pöytä is front, so the ending is -ltä, and t softens to d.
✅ Ota kirja pöydältä.
Take the book off the table.
Key Takeaways
- Many case endings have two shapes: a back a-shape (-ssa, -sta, -lla, -lta, -na, -a) and a front ä-shape (-ssä, -stä, -llä, -ltä, -nä, -ä).
- The stem decides: a back word takes the a-shape, a front word the ä-shape.
- Both real front words (kylä, käsi) and neutral-only words (meri, vesi, tie) take the ä-shape → kädessä, meressä, vedessä.
- The genitive -n and translative -ksi never alternate — attach them without a second thought.
- Only the vowel changes; the consonants of the ending stay exactly the same.
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Start learning Finnish→Related Topics
- Suffix Vowel Pairs: a/ä, o/ö, u/yA2 — Beyond the familiar -a/-ä, Finnish suffixes also alternate o/ö and u/y — the sneaky -tu/-tty participle included. Neutral e and i have no partner.
- Vowel Harmony: How Suffix Vowels Are ChosenA1 — A word's own vowels decide whether its endings take the back (a/o/u) or front (ä/ö/y) shape — one rule running through every suffix in Finnish.
- A Suffix Master TableA2 — The one-page cheat sheet: every alternating case ending in both shapes (talossa/kylässä), plus the invariant endings (-n, -lle, -ksi, -kin) that never harmonize.
- -ssa vs -lla: 'in' vs 'on/at'A2 — How to choose the inessive -ssa (inside) over the adessive -lla (on a surface, or at an exterior place) — the interior/exterior split, plus the fixed exterior nouns.
- Inessive -ssa/-ssä: 'in'A1 — The inessive -ssa/-ssä means 'inside' (talossa, Helsingissä): location within, time within, and set idioms — and the ending forces the weak grade.