þekkja means "to know" in the sense of being acquainted with — knowing a person, a place, a song, a face. English has only one verb "know" and lets context sort out the rest; Icelandic, like German (kennen/wissen/können) and the Romance languages, splits the territory three ways. Getting þekkja right therefore means getting its boundaries right: when to reach for þekkja, and when vita or kunna is the only correct choice. This page gives the full paradigm and then devotes a full section to that three-way split, which is the single thing learners get wrong most often.
Conjugation
Class: weak, Class 1 j-verb (stem in -j-, surfacing before -a/-u endings). Auxiliary: hafa — ég hef þekkt "I have known."
| Principal parts | |
|---|---|
| Infinitive | að þekkja |
| 3sg present | þekkir |
| 3sg past | þekkti |
| Supine | þekkt |
| Person | Present (nútíð) | Past (þátíð) |
|---|---|---|
| ég | þekki | þekkti |
| þú | þekkir | þekktir |
| hann / hún / það | þekkir | þekkti |
| við | þekkjum | þekktum |
| þið | þekkið | þekktuð |
| þeir / þær / þau | þekkja | þekktu |
| Person | Present subjunctive | Past subjunctive |
|---|---|---|
| ég | þekki | þekkti |
| þú | þekkir | þekktir |
| hann / hún / það | þekki | þekkti |
| við | þekkjum | þekktum |
| þið | þekkið | þekktuð |
| þeir / þær / þau | þekki | þekktu |
| Non-finite & imperative | |
|---|---|
| Imperative (þú) | þekktu |
| Imperative (þið) | þekkið |
| Supine | þekkt |
| Past participle (m/f/n) | þekktur / þekkt / þekkt ("known, well-known") |
| Middle voice (miðmynd) | þekkjast — "to know each other; to be recognisable" |
Pronunciation: the preaspirated -kk-
The double kk in þekki, þekkti, þekkt is not pronounced as a long [k]. Icelandic preaspirates it: you hear a little puff of breath before the stop, roughly [ˈθɛʰkːɪ] — like the -ck- in an emphatic English "back!". Beginners who pronounce þekki with a plain "k" sound noticeably off; the breathy catch before the k is what makes it sound native. The same preaspiration shows up in takk (thanks) and ekki (not), so it is everywhere.
Ég þekki hana vel — við vorum saman í skóla.
I know her well — we were in school together.
Þekkir þú einhvern góðan tannlækni?
Do you know a good dentist?
Ég þekkti hann strax, þótt mörg ár væru liðin.
I recognised him immediately, even though many years had passed.
Object case: þekkja + accusative
The thing or person you know is the direct object in the accusative: ég þekki hann (acc.), ég þekki *þennan stað* (acc.). There is no preposition. English speakers sometimes try to slip in a "to" or "about" — don't; þekkja takes a bare accusative object.
Þekkirðu þessa götu? Ég er alveg týnd.
Do you know this street? I'm completely lost.
Allir þekkja þetta lag.
Everyone knows this song.
The three-way split: þekkja vs vita vs kunna
This is the heart of the matter. Where English says "know" for all three, Icelandic forces a choice based on what kind of knowing you mean.
| Verb | Meaning of "know" | Typical object | Example |
|---|---|---|---|
| þekkja | be acquainted with | a person, place, thing | Ég þekki hana. (I know her.) |
| vita | know a fact / that-clause | a fact, information | Ég veit það. (I know that.) |
| kunna | know how / know by heart | a skill, a language, a poem | Ég kann íslensku. (I know Icelandic.) |
The logic: þekkja is recognition through experience — you've encountered the person or place. vita is holding a fact — it pairs naturally with að "that": ég veit að hann kemur ("I know that he's coming"). kunna is ability or memorised mastery — you can do it: speak a language, ride a bike, recite a verse. A handy probe: if you could rephrase English "know" as "be familiar with," use þekkja; as "know that…," use vita; as "know how to / can," use kunna.
Ég þekki Reykjavík vel, en ég veit ekki hvar þessi búð er.
I know Reykjavík well, but I don't know where this shop is.
Hún kann þrjú tungumál og þekkir hálfan bæinn.
She knows three languages and knows half the town.
Common Mistakes
❌ Ég þekki að hann kemur á morgun.
Incorrect — knowing a fact/that-clause is vita, not þekkja
✅ Ég veit að hann kemur á morgun.
I know (that) he's coming tomorrow.
❌ Ég þekki íslensku.
Incorrect if you mean you speak it — knowing a language as a skill is kunna
✅ Ég kann íslensku.
I know / can speak Icelandic.
❌ Ég þekji hann ekki.
Incorrect — the present 1sg keeps the i and drops the j: þekki, not þekji
✅ Ég þekki hann ekki.
I don't know him.
❌ Ég þekkti til hennar í mörg ár.
Incorrect — þekkja takes a bare accusative object, no til; þekkja til (gen.) exists but means 'know of / be aware of', a different shade
✅ Ég þekkti hana í mörg ár.
I knew her for many years.
Key Takeaways
- þekkja / þekkir / þekkti / þekkt — a weak j-verb; the j appears before -a/-u (þekkja, þekkjum) and disappears before -i and in the past (þekki, þekkti).
- Means "know" as be acquainted with — a person, place, or thing — and takes a bare accusative object.
- The -kk- is preaspirated: a puff of breath before the k.
- Don't overstretch it: vita for facts (ég veit að…), kunna for skills and memorised things (ég kann íslensku).
- Auxiliary is hafa: ég hef þekkt. Participle þekktur also means "well-known, famous."
Now practice Icelandic
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Start learning Icelandic→Related Topics
- vita vs kunna vs þekkja: Three Ways to 'Know'A2 — A decision guide for the three Icelandic verbs that all translate as English 'know' — vita for facts, kunna for skills and memorised content (including languages), and þekkja for being acquainted with a person or place.
- vita (to know a fact)A2 — Full conjugation of the preterite-present verb vita (veit / vissi / vissu / vitað), its 'know-a-fact' semantics versus kunna ('know how') and þekkja ('be acquainted with'), the að-clause complement, the phrases vita af and vita um, and the set phrase að því er ég best veit.
- Preaspiration: hp, ht, hk and pp, tt, kkA2 — Icelandic's signature sound: a puff of breath that comes BEFORE the stops written pp, tt, kk (and clusters like pn, tn, kn) — so epli is [ˈɛhplɪ] and nótt is [nouht]. The h falls before the stop, the mirror image of English aspiration, and it is one of the rarest features in the world's languages.