'know': tietää, tuntea, osata | Finnish Grammar

English gets by with a single verb "know" for three quite different ideas, and Finnish splits them into three separate verbs that are not interchangeable. tietää = know a fact or piece of information. tuntea = be acquainted with a person or place (and, as a bonus, "to feel"). osata = know how to do something — a skill. This page is the decision rule; the full conjugations live on each verb's reference page.

The one decision

Ask what kind of "knowing" you mean:

A fact, information, an answer, that something is so → tietää
A person or place you are familiar with → tuntea
An ability — you can do it → osata

The core minimal pair is about a person versus a fact about that person:

Tiedän hänen nimensä.

I know his name. (a fact — tietää)

Tunnen hänet.

I know him. (acquaintance — tuntea)

You can hold both at once — you may know his name (a fact) without knowing him (acquaintance) — and Finnish forces you to say which one you mean.

tietää = facts and information

tietää takes a fact-like object (an answer, a name, a time, a piece of news) or a whole että-clause. It is the verb behind "I know that…" and behind the everyday "I don't know."

Tiedän vastauksen.

I know the answer.

Tiedätkö, mihin aikaan juna lähtee?

Do you know what time the train leaves?

Anteeksi, en tiedä.

Sorry, I don't know. (the everyday phrase)

Tiedän, että hän asuu Turussa.

I know that he lives in Turku. (tietää + että-clause)

tuntea = people, places, and feeling

tuntea is "to be acquainted with." Its object is a person or a place you are personally familiar with — not facts about them.

Tunnetko sinä Marian?

Do you know Maria? (are you acquainted with her?)

Tunnen tämän kaupungin hyvin.

I know this city well. (I'm familiar with it)

Note the contrast with tietää: tunnen Helsingin means "I know Helsinki (I find my way around)," while tiedän Helsingistä paljon means "I know a lot about Helsinki (facts)." Familiarity is tuntea; information is tietää.

The same verb also means to feel / to sense a physical or emotional state — a meaning that surprises learners who only met it as "know a person."

Tunnetko tuulen?

Do you feel the wind?

Tunnen oloni hyväksi tänään.

I feel good today. (literally: I feel my state good)

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When the object of tuntea is a person or personal pronoun, it takes the full accusative object form: hänet, sinut, minut, meidät, teidät, heidät — never the bare nominative. Say tunnen hänet, not tunnen hän. Under negation it flips to the partitive: en tunne häntä ("I don't know him").

osata = skills and know-how

osata is "to know how to." It takes an infinitive (osaan uida "I know how to swim") or, for a language or craft, a partitive noun (osaan suomea "I know Finnish"). If you can rephrase the English as "I can / I'm able to (do)," it is osata.

Osaan uida.

I know how to swim.

Osaatko puhua suomea?

Can you speak Finnish? (do you know how?)

Hän osaa soittaa pianoa.

She can play the piano.

Osaan vähän ranskaa.

I know a little French. (a language as a skill → osata + partitive)

That last example is a favourite trap: a language you have learned is a skill, so it is osata, not tietää. You "know how to use" French; you do not "know the fact of" French.

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If you also speak German or French, the split maps almost exactly: tietää ≈ German wissen / French savoir (a fact); tuntea ≈ kennen / connaître (be acquainted); osata ≈ können / savoir + infinitive (a skill). English is the odd one out for lumping all three into "know."

Watch the consonant gradation

All three verbs change their stem consonant in the present tense — a common source of misspellings.

Verb	Meaning	"I …" (1sg)	Gradation
tietää	know a fact	tiedän	t → d
tuntea	know a person / feel	tunnen	nt → nn
osata	know how to	osaan	(contracted -ta verb)

Why English speakers get this wrong

Because one English word covers all three, learners pick whichever Finnish verb they learned first and use it everywhere — usually tietää, since it is the most frequent. The result is tiedän hänet for a person (should be tunnen hänet) or tiedän uida for a skill (should be osaan uida). The fix is to translate the idea, not the word: fact → tietää, familiarity → tuntea, ability → osata. For the finer line between "know how to" (osata) and "be allowed / able to" (voida, saada), see the 'can' verbs.

Common Mistakes

❌ Tiedän hänet.

Incorrect — a person is acquaintance, not a fact: tunnen hänet.

✅ Tunnen hänet.

I know him.

❌ Tiedän uida.

Incorrect — a skill needs osata: osaan uida.

✅ Osaan uida.

I know how to swim.

❌ Tunnen vastauksen.

Incorrect — an answer is a fact, so tietää: tiedän vastauksen.

✅ Tiedän vastauksen.

I know the answer.

❌ Tiedän suomea.

Incorrect — a language is a skill: osaan suomea.

✅ Osaan suomea.

I know Finnish.

❌ Osaan, että hän tulee.

Incorrect — knowing a fact-clause is tietää: tiedän, että…

✅ Tiedän, että hän tulee.

I know that he's coming.

Key Takeaways

tietää = a fact / information / an että-clause — tiedän vastauksen, tiedän, että…
tuntea = acquaintance with a person or place (object in the accusative: hänet, sinut), and also "to feel/sense."
osata = a skill — takes an infinitive (osaan uida) or a language/craft in the partitive (osaan suomea).
Translate the idea: fact → tietää, familiarity → tuntea, ability → osata.
Mind the gradation: tiedän (t→d), tunnen (nt→nn), osaan.

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