English has one overworked verb for an enormous range of ideas: I know him, I know that it's raining, I know German, I know how to swim. German splits this single word across three verbs — kennen, wissen, and können — and choosing the wrong one is one of the most persistent errors English speakers make, because the source language gives you no hint that a choice even exists. The good news is that the three carve up the territory cleanly, and once you see the logic you can predict the right verb every time.
The companion page choosing/wissen-vs-kennen handles the two-way contrast that beginners meet first; this page adds the third member, können, which is where English speakers most often go wrong — because "I know a language" and "I know how to do something" feel like knowing, but in German they are matters of skill, and skill belongs to können.
The one rule that decides all three
Ask what kind of knowing you mean:
| What you "know" | Verb | What follows it |
|---|---|---|
| A person, place, or thing — you are acquainted with it | kennen | A direct (accusative) object — never a clause |
| A fact or piece of information | wissen | A clause (dass / ob / wo …) or es / das / die Antwort |
| How to do something — a learned skill or a language | können | An infinitive (schwimmen) or a bare object for languages (Deutsch) |
In one line: object → kennen; fact/clause → wissen; skill/language → können.
Ich kenne ihn schon seit der Schulzeit.
I've known him since our school days.
Ich weiß, dass er morgen kommt.
I know that he's coming tomorrow.
Ich kann gut schwimmen.
I can swim well. / I know how to swim well.
kennen — acquaintance and familiarity
kennen (regular: ich kenne, du kennst, er kennt; past kannte) means to be acquainted with something — to have it in your circle of experience. Its object is a noun in the accusative: a person, a place, a song, a book, a feeling. The crucial structural fact for English speakers is that kennen never takes a clause. You cannot kennen, dass …. If a "that"-clause would follow, you need wissen instead.
Kennst du Berlin? — Ja, ich war schon dreimal dort.
Do you know Berlin? — Yes, I've been there three times.
Ich kenne dieses Lied, aber ich weiß nicht, wie es heißt.
I know this song, but I don't know what it's called.
Notice the second example: kennen for the song (a thing you're acquainted with), wissen for the fact of its title (information, introduced by wie). The same English "know" appears twice; German splits it because the two kinds of knowing are different.
wissen — facts and information
wissen is irregular and worth memorising: ich weiß, du weißt, er weiß (singular with weiß, written with ß), then regular plural wir wissen, ihr wisst, sie wissen; past wusste. It means to know a fact, and it typically takes a subordinate clause introduced by dass (that), ob (whether), or a w-word (wo, wann, warum, wie), or else a neuter pronoun like es or das, or die Antwort.
Weißt du, wo der Bahnhof ist?
Do you know where the station is?
Ich weiß es nicht, tut mir leid.
I don't know, sorry.
Niemand weiß, ob der Zug pünktlich kommt.
Nobody knows whether the train will arrive on time.
If you can rephrase the English with "know the fact that …" or "know whether/where/why …", you want wissen.
können — skills, abilities, and languages
This is the member English speakers forget exists in this role. können (modal verb: ich kann, du kannst, er kann; past konnte) is best known as "can / to be able to," but it is also the German verb for knowing how to do something — any learned ability. Crucially, this includes languages.
Ich kann Deutsch, aber mein Französisch ist eingerostet.
I know German, but my French is rusty.
Sie kann Klavier spielen und auch ein bisschen Geige.
She can play the piano and a bit of violin too.
Kannst du kochen? — Na ja, Nudeln schon.
Can you cook? — Well, pasta at least.
Two patterns to absorb:
- Skills with an infinitive: Ich kann schwimmen (I know how to swim), Ich kann Auto fahren (I know how to drive). German uses the bare infinitive at the end; there is no zu, because können is a modal.
- Languages with a bare noun, no article: Ich kann Deutsch / Englisch / Spanisch. Note: no article — not ein Deutsch, not das Deutsch in this construction. The language name stands alone.
Why English merges what German splits
English collapsed an older distinction. Old English had cunnan (to know how, the ancestor of modern "can") alongside witan (to know a fact, the cousin of German wissen — preserved in the fossil "to wit"). Over centuries "know" swallowed most of witan's and cunnan's territory, leaving "can" only the auxiliary "be able to." German kept all three verbs fully alive and productive. So when you reach for German können to say Ich kann Deutsch, you are reactivating a distinction English speakers once made too — it only feels foreign.
A quick decision flow
- Is the thing known a noun you're acquainted with (person, place, song, city)? → kennen.
- Is it a fact, something you could put after "that / whether / where / why," or es / das? → wissen.
- Is it a skill, ability, or language — something you learned to do? → können.
Ich kenne den Pianisten persönlich, ich weiß, dass er heute spielt, aber ich kann selbst kein Klavier.
I know the pianist personally, I know that he's playing today, but I myself can't play piano.
That single sentence uses all three verbs correctly — kennen for the person, wissen for the fact, können for the (missing) skill.
Common Mistakes
❌ Ich weiß ihn schon lange.
Incorrect — a person is acquaintance, not a fact; needs kennen.
✅ Ich kenne ihn schon lange.
I've known him for a long time.
❌ Ich kenne, dass du recht hast.
Incorrect — kennen never takes a clause; a fact needs wissen.
✅ Ich weiß, dass du recht hast.
I know that you're right.
❌ Ich weiß Deutsch.
Incorrect — a language is a skill, not a fact; needs können.
✅ Ich kann Deutsch.
I know German.
❌ Ich kenne Deutsch.
Incorrect — a language is a learned skill, not an acquaintance; needs können.
✅ Ich kann Deutsch.
I know German.
❌ Ich weiß schwimmen.
Incorrect — knowing how to do something is können + infinitive.
✅ Ich kann schwimmen.
I know how to swim.
Key Takeaways
- One English "know" becomes three German verbs.
- kennen = be acquainted with a person/place/thing; takes an accusative object, never a clause.
- wissen = know a fact; takes a dass/ob/w-clause or es/das; irregular singular ich weiß.
- können = know how to do something or know a language; Ich kann schwimmen, Ich kann Deutsch (no article).
- When in doubt, ask: object → kennen, fact → wissen, skill → können.
Now practice German
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Start learning German→Related Topics
- wissen vs kennen (to know)A2 — German splits English 'know' into wissen (know a fact, + clause) and kennen (be acquainted with a person, place, or thing) — with können for knowing a skill.
- kennen: Full Conjugation and UsageA2 — Complete conjugation of kennen 'to know / be acquainted with', a mixed verb, with its accusative valency, the kennen vs. wissen vs. können distinction, and the errors English speakers make.
- wissen: Full Conjugation and UsageA2 — Complete conjugation of wissen 'to know (facts)' across every tense and mood, including its modal-like irregular present (weiß/weißt/weiß), the wusste/wüsste forms, the crucial contrast with kennen, and the errors English speakers make.
- können: Ability, Possibility, PermissionA2 — The full conjugation and meanings of können — ability, possibility and informal permission — plus the könnte / konnte trap that turns on a single umlaut.
- können: Full Conjugation and UsageA2 — Complete conjugation of the modal verb können 'can / to be able' across every tense and mood, with the double-infinitive Perfekt, the polite könnte, and the errors English speakers make.