The clean past forms — puhuin, sanoin, tulin — are only half the story. When the past marker -i- meets a stem that ends in a, ä, or short i, or a stem built on a t, the two sounds cannot simply sit side by side, and something gives. Three verbs make the point: from the identical marker, antaa yields antoi (the a becomes o), ottaa yields otti (the a drops), and haluta yields halusi (a t turns into s). Same -i-, three different outcomes. This page maps them all.
Be warned up front: some of these outcomes are lexically fixed — you cannot always predict them from the spelling. Antaa and ottaa look like twins, yet they split. Where a rule exists, this page gives it; where memorisation is the only path, it says so plainly.
The master table of outcomes
| Stem ends in… | Before -i- | Example |
|---|---|---|
| u, y, o, ö | stays (diphthong) | puhu- → puhui |
| e | drops | luke- → luki, itke- → itki |
| short i | merges into one i | etsi- → etsi, oppi- → oppi |
| a (1st vowel a or e) | a → o | anta- → antoi, maksa- → maksoi |
| a (1st vowel i, o, u) | a drops | osta- → osti, muista- → muisti |
| ä | drops | elä- → eli, vetä- → veti |
| -taa/-tää after long V/diphthong | t → s | tietä- → tiesi, huuta- → huusi |
| Type 4 -ata/-ätä | t → s | haluta → halusi, tavata → tapasi |
The first three rows are the regular cases. The rest are what this page drills.
a-stems: the a → o versus a-drop split
This is the hard one, so take it slowly. For a two-syllable verb whose stem ends in -a, the fate of that a depends on the vowel in the first syllable:
- First-syllable vowel a or e → the final a becomes o.
- First-syllable vowel i, o, or u → the final a drops.
So anta- (first vowel a) → antoi, but osta- (first vowel o) → osti. The rule is reliable, but notice it hinges on a vowel that has nothing to do with the ending — you have to look back at the start of the word.
| a → o (1st vowel a/e) | Past 3sg | a drops (1st vowel i/o/u) | Past 3sg |
|---|---|---|---|
| antaa (give) | antoi | ostaa (buy) | osti |
| maksaa (cost/pay) | maksoi | muistaa (remember) | muisti |
| auttaa (help) | auttoi | nostaa (lift) | nosti |
| laulaa (sing) | lauloi | kirjoittaa (write) | kirjoitti |
| kaataa (pour/fell) | kaatoi | loistaa (shine) | loisti |
Gradation still operates on top of this. Antaa weakens nt → nn in the closed-syllable forms, so the full past is annoin, annoit, *antoi, annoimme, annoitte, antoivat — *o throughout, but nt only in the two open-syllable (3sg/3pl) forms. Auttaa likewise: autoin, autoit, *auttoi, autoimme, autoitte, auttoivat*. See consonant gradation in verbs for the mechanics.
Kuka antoi sinulle tämän osoitteen?
Who gave you this address?
Eilen satoi vettä koko päivän.
Yesterday it rained all day.
Ostin uuden puhelimen, koska vanha hajosi.
I bought a new phone because the old one broke.
En muistanut hänen nimeään, mutta muistin kasvot.
I didn't remember his name, but I remembered the face.
The antaa / ottaa lesson: rules help, but memorise the split
The reason antaa → antoi but ottaa → otti is exactly the rule above: antaa has first-syllable a (→ o), ottaa has first-syllable o (→ drop). But learners still trip here, because the two verbs are so similar in shape and meaning-frequency. The honest advice: learn the rule, and also just memorise the past 3sg of the high-frequency a-stems as fixed forms — antoi, otti, maksoi, osti, kirjoitti — so you never have to compute them mid-sentence.
Otin taksin, koska myöhästyin bussista.
I took a taxi because I missed the bus.
Maksoin laskun heti, jottei se unohtuisi.
I paid the bill right away so it wouldn't be forgotten.
Kirjoitin sinulle pitkän viestin eilen illalla.
I wrote you a long message last night.
t → s: the assibilation verbs
A distinct group turns a stem-final t into s before -i-. Historically this is the old ti → si change, and it shows up in two places.
(1) -taa/-tää after a long vowel or diphthong. Here the whole taa/tää becomes si:
| Verb | Past 3sg | Verb | Past 3sg |
|---|---|---|---|
| tietää (know) | tiesi | löytää (find) | löysi |
| huutaa (shout) | huusi | pyytää (ask/request) | pyysi |
| lentää (fly) | lensi | ymmärtää (understand) | ymmärsi |
Contrast this with pitää (short i before tää) → piti and vetää (short e) → veti: with a short first-syllable vowel the ä just drops in the ordinary way, and there is no s. The t → s switch needs the long vowel or diphthong (or a preceding l, r, n, as in lensi, ymmärsi, kielsi).
(2) Type 4 verbs in -ata/-ätä. These form the past on -si as well:
| Verb | Past: minä / hän |
|---|---|
| haluta (want) | halusin / halusi |
| tavata (meet) | tapasin / tapasi |
| pelata (play) | pelasin / pelasi |
Tiesin heti, että jotain oli vialla.
I knew right away that something was wrong.
Löysin avaimet vasta seuraavana aamuna.
I only found the keys the next morning.
Halusin vain auttaa, en loukata ketään.
I only wanted to help, not to offend anyone.
He tapasivat ensimmäisen kerran yliopistossa.
They met for the first time at university.
i-stems: the two i's merge
Verbs whose stem ends in a short i (many -ia/-iä verbs) do not gain a visible marker at all — the stem i and the past i collapse into a single i. The result: for these verbs the past looks like the present with the 3sg vowel-lengthening removed.
| Verb | Present 3sg | Past 3sg |
|---|---|---|
| etsiä (search) | etsii | etsi |
| oppia (learn) | oppii | oppi |
| vaatia (demand) | vaatii | vaati |
Because the marker vanishes, the minä/sinä/me/te forms of these verbs are identical in present and past — etsin is both "I search" and "I searched"; only the 3sg (etsii vs etsi) and context keep them apart.
Hän etsi avaimia kaikkialta, mutta turhaan.
She looked for the keys everywhere, but in vain.
Poika oppi uimaan jo viisivuotiaana.
The boy learned to swim at just five years old.
e-stems (a reminder)
Consonant + e stems drop the e — lukea → luki, itkeä → itki — exactly as on the regular page. With gradation this can hide the consonant too: lukea gives luin, luit, *luki, luimme, luitte, lukivat (the *k survives only in the open-syllable 3sg/3pl).
Luin koko kirjan yhdessä illassa.
I read the whole book in one evening.
Common Mistakes
❌ Hän antai minulle lahjan.
Incorrect — antaa's a raises to o, not stays: antoi.
✅ Hän antoi minulle lahjan.
She gave me a gift.
❌ Ostoin uuden takin eilen.
Incorrect — ostaa's a drops (1st vowel o), it does not go to o: ostin.
✅ Ostin uuden takin eilen.
I bought a new coat yesterday.
❌ Minä tietin sen jo etukäteen.
Incorrect — tietää assibilates t → s: tiesin.
✅ Tiesin sen jo etukäteen.
I knew it already in advance.
❌ He halutivat lähteä aikaisin.
Incorrect — Type 4 haluta forms the past on -si: halusivat.
✅ He halusivat lähteä aikaisin.
They wanted to leave early.
Key Takeaways
- a-stems split by first-syllable vowel: a/e → o (antoi, maksoi, lauloi); i/o/u → a drops (osti, muisti, kirjoitti).
- ä-stems always drop the ä — never ö (eli, veti, heitti).
- t → s in long-vowel/diphthong -taa/-tää (tiesi, huusi, löysi) and in Type 4 -ata/-ätä (halusi, tapasi).
- i-stems merge the two i's (etsi, oppi), so most past forms equal the present.
- Where the split is not predictable from spelling, memorise the past 3sg of the common verbs. Continue with the Type-2 contractions.
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Start learning Finnish→Related Topics
- Forming the Past: Regular CasesA2 — The clean past: stems in u/y/o/ö just add -i- (puhuin, sanoin), and consonant + e stems drop the e (tulin, menin, luin).
- Past of Type 2: söi, joi, sai, veiB2 — Type 2 long-vowel/diphthong stems contract with the past -i-: saada→sai, syödä→söi, juoda→joi, viedä→vei, plus tehdä→teki, nähdä→näki.
- Gradation in the Past TenseB1 — The past keeps the same weak-in-closed, strong-in-open split — antaa gives annoin but antoi, with the a→o shift folded in.
- antaa ('to give')A2 — Full conjugation of antaa (to give), a Type 1 verb with nt↔nn gradation, plus its rection: allative recipient + total/partitive object.