Weak verbs build the past by tacking an ending onto the stem. Strong verbs do something older and stranger: they change the vowel inside the stem and add no ending at all. Synge becomes sang; drikke becomes drak; finde becomes fandt. This vowel change is called ablaut (Danish aflyd), and it is the same machinery that turns English sing into sang and drink into drank. There are only about 130 strong verbs in Danish, but they are the most-used verbs in the language, so you cannot avoid them — and you shouldn't want to, because once you see the families, they are far more orderly than they first appear.
Three forms, not two
A weak verb really only asks you to learn one thing beyond the present: the ending. A strong verb asks for three principal parts, because the participle vowel is often different again from the past vowel.
| Infinitive | Past (datid) | Past participle |
|---|---|---|
| at synge (to sing) | sang | (har) sunget |
| at drikke (to drink) | drak | (har) drukket |
| at finde (to find) | fandt | (har) fundet |
| at skrive (to write) | skrev | (har) skrevet |
| at give (to give) | gav | (har) givet |
| at tage (to take) | tog | (har) taget |
| at se (to see) | så | (har) set |
| at få (to get/receive) | fik | (har) fået |
Notice that the participle almost always still carries a weak-style ending — -et (sunget, fundet, skrevet, taget) — even though the vowel it sits on is supplied by ablaut. So a strong participle is a hybrid: ablaut vowel + the familiar -et. Many double the final consonant (drukket, drak → drukket) because the preceding vowel is short.
Vi sang fødselsdagssangen, og bagefter spiste vi kage.
We sang the birthday song, and afterwards we ate cake.
Jeg fandt mine nøgler i lommen, lige da jeg gav op.
I found my keys in my pocket, just as I was giving up.
Hun skrev et langt brev til sin mormor.
She wrote a long letter to her grandmother.
Learn them in vowel families, not one by one
This is the whole trick. Strong verbs are not random; they cluster into ablaut series — recurring vowel triples shared by groups of verbs. Learn one verb in a series well, and its siblings fall into place because they march through the same vowels. Below are the four most productive families for a learner.
Series 1 — i → a → u
The classic "nasal" family, where the present i lowers to a in the past and rounds to u in the participle. If you know English sing–sang–sung, you already own the pattern.
| Infinitive | Past | Participle |
|---|---|---|
| at finde (find) | fandt | (har) fundet |
| at drikke (drink) | drak | (har) drukket |
| at synge (sing) | sang | (har) sunget |
De drak kaffe og snakkede, til solen gik ned.
They drank coffee and talked until the sun went down.
Series 2 — i → e (→ e or i)
A long-i present drops to a long e in the past. The participle usually keeps that e (skrevet, blevet), but a few members snap back to a short i (bide → bed → bidt), so check the participle rather than assuming it. English write–wrote–written is the cousin, and notice that English does the same thing — its participle vowel drifts away from the past too.
| Infinitive | Past | Participle |
|---|---|---|
| at skrive (write) | skrev | (har) skrevet |
| at bide (bite) | bed | (har) bidt |
| at blive (become/stay) | blev | (er) blevet |
Hunden bed aldrig nogen, men den blev hjemme hele dagen.
The dog never bit anyone, but it stayed home all day.
Series 3 — e/i → a → e/i
A front vowel in the present drops to a in the past (gav, så, sad) and then returns to a front vowel in the participle (givet, set, siddet). The hallmark of this family is the a in the past form; the participle settles back toward the original vowel. Give and se live here.
| Infinitive | Past | Participle |
|---|---|---|
| at give (give) | gav | (har) givet |
| at se (see) | så | (har) set |
| at sidde (sit) | sad | (har) siddet |
Vi sad i haven og så solnedgangen, mens han gav os et tæppe.
We sat in the garden and watched the sunset while he gave us a blanket.
Series 4 — a/å → o → a/å
A low present vowel rounds to o in the past (tog, for, stod); the participle then settles on an a-quality vowel (taget, faret, and stået with å). The reliable signature of this family is the o in the past. Tage and fare are the anchors.
| Infinitive | Past | Participle |
|---|---|---|
| at tage (take) | tog | (har) taget |
| at fare (rush/dash) | for | (er) faret |
| at stå (stand) | stod | (har) stået |
Hun tog toget klokken otte og stod af i Odense.
She took the train at eight and got off in Odense.
A few high-frequency loners
Not every strong verb fits a tidy series, and the very commonest ones are often the most irregular precisely because heavy use protects old forms from being smoothed out. At få and at se are worth memorising outright.
Jeg fik et brev fra banken og så straks, at noget var galt.
I got a letter from the bank and saw at once that something was wrong.
Har du set min jakke? Jeg fik den til jul.
Have you seen my jacket? I got it for Christmas.
A note on the participle used as an adjective
After har, the participle is fixed in its -et form: jeg har skrevet, jeg har drukket. But strong participles also lead a second life as adjectives, and there they agree with their noun like any adjective — the common-gender form often ends in -en. So skrevet (the verb form) sits beside et skrevet ord / det skrevne ord as a modifier, and you will meet older or fixed forms like en drukken mand ("a drunken man"). For building tenses, always reach for -et; the -en forms belong to the adjective system and are worth recognising rather than producing at this stage.
Jeg har drukket te, men han er en drukken nar.
I have drunk tea, but he's a drunken fool. (verb participle -et vs adjectival -en)
How this differs from English
English speakers have an enormous head start here that is easy to overlook. English kept its own strong verbs: sing/sang/sung, drink/drank/drunk, write/wrote/written, give/gave/given, take/took/taken, see/saw/seen, find/found/found. These are the same verbs with the same ablaut logic, because Danish and English are both Germanic. So your job is not to learn an alien system — it is to learn the Danish output of a system your mouth already runs. The danger is the reverse: trusting the English form too closely. Danish blive ("become/stay") looks like English believe but behaves like blew; fandt ("found") has a -t that English lost. Use English to spot the family, then learn the Danish vowel exactly.
Common Mistakes
❌ Vi syngede fødselsdagssangen.
Wrong — regularising a strong verb. Synge is strong: the past is sang.
✅ Vi sang fødselsdagssangen.
Correct — sang, with no ending.
❌ Jeg findede mine nøgler.
Wrong — finde is strong; you cannot add a weak ending to it.
✅ Jeg fandt mine nøgler.
Correct — fandt.
❌ Han har skrev et brev.
Wrong — skrev is the past tense, not the participle. After har you need the participle.
✅ Han har skrevet et brev.
Correct — har + the participle skrevet.
❌ Hun har drak for meget kaffe.
Wrong — drak is the past; the participle is different again.
✅ Hun har drukket for meget kaffe.
Correct — har + drukket.
Key Takeaways
- Strong verbs change the stem vowel (ablaut) and add no past ending: finde → fandt.
- They have three principal parts, because the participle vowel often differs from the past vowel: drikke → drak → drukket.
- Learn them in vowel families keyed to the past vowel (i–a–u, i–e, e/i–a, a–o), not individually — then confirm each participle, which can spring back toward the present vowel (bidt, givet, set).
- They are the highest-frequency verbs in Danish — and most map onto English strong verbs you already know. Use English to find the family; learn the Danish vowel exactly.
Now practice Danish
Reading grammar gets you part of the way. The exercises are where it sticks — free, no signup needed.
Start learning Danish→Related Topics
- The Past Tense: An OverviewA1 — How the Danish simple past (datid) splits into weak -ede, weak -te, and strong (vowel-change) verbs — and why you must learn each verb's class.
- Weak Past: The -ede ClassA1 — The largest, productive class of Danish regular verbs — past in -ede, participle in -et — and the safe default for any verb you don't recognise.
- Weak Past: The -te ClassA2 — The second weak class of Danish verbs — past in -te, participle in -t — and how to tell it apart from the larger -ede class.
- The Present PerfectA2 — How Danish builds the present perfect with have (or være) plus the past participle — and the one rule English speakers need: definite past time takes the simple past, not the perfect.
- The Present TenseA1 — How to form the Danish present (add -r) and why one present form covers English's simple present, present continuous, and 'going to' future.