Dækket er fladt, så vi må ikke køre videre.

In Danish, the definite article is usually added to the end of the noun.

• et dæk = a tire / a tyre
• dækket = the tire

So -et is the neuter singular definite ending.

Also, dæk can mean different things in other contexts, such as deck or covering, but here it means tire because of the context and because something is fladt.

Because dæk is a neuter noun: et dæk.

When an adjective is used after er and describes a neuter singular noun, it usually takes -t:

• en bil er flad would be wrong here because bil is not something you normally call flat in the same way
• et dæk er fladt = a tire is flat

So:

• flad = common gender / base form
• fladt = neuter singular
• flade = plural or definite form in many contexts

Here så means so, therefore, or as a result.

It connects the two ideas:

• Dækket er fladt = the tire is flat
• så vi må ikke køre videre = so we must not / cannot continue driving

It shows cause and result.

Because here så is linking two main clauses, similar to English so.

That means the second clause keeps normal main-clause word order:

• vi må ikke køre videre

So the structure is:

• statement 1 + så
  • statement 2

If så were being used more like then at the start of a clause, you could get inversion:

• Så må vi ikke køre videre

That version is possible in some contexts, but it sounds a bit different in rhythm and emphasis. In your sentence, så vi må ikke... is the straightforward so we mustn't... pattern.

Må ikke literally often means must not or may not.

In real usage, though, it can cover a few English ideas depending on context:

• not allowed to
• must not
• should not
• sometimes something close to can't, if the situation makes it impossible or unsafe

In this sentence, with a flat tire, the natural idea is that continuing to drive is not acceptable / not safe / not something we can properly do.

A related form is kan ikke, which is more directly cannot in the sense of ability or possibility.

So:

• vi kan ikke køre videre = we can’t continue driving
• vi må ikke køre videre = we mustn’t / we’re not supposed to continue driving

Because after a modal verb like må, Danish uses the bare infinitive.

So you say:

• må køre
• kan køre
• skal køre
• vil køre

not:

• må at køre

This is similar to English:

• must drive
• can drive

not must to drive.

In a main clause, ikke usually comes after the finite verb and before the infinitive or other non-finite part.

So:

• vi må ikke køre videre

Breakdown:

• vi = subject
• må = finite verb
• ikke = negation
• køre = infinitive
• videre = adverb

This is a very common Danish pattern with modal verbs.

Videre means further, on, or onward.

With a verb like køre, it often means continue:

• køre videre = drive on / keep driving / continue driving

So the sentence is not just about driving in general. It means continuing from where you are.

Yes, but it sounds less natural here.

• køre videre is the normal, everyday way to say drive on / continue driving
• fortsætte med at køre is more literally continue driving, but it is heavier and less idiomatic in this situation

In a sentence about a flat tire, Danes would very naturally say vi må ikke køre videre.

The hardest parts for English speakers are usually æ, ø, and the soft Danish pronunciation.

A rough guide:

• dækket: the æ is somewhat like the vowel in cat, but not exactly
• må: the å is somewhat like the vowel in more for many speakers, but shorter and rounder
• køre: the ø has no exact English equivalent; round your lips while trying to say something like eh
• videre: the d is often softer than an English d

A very rough English-style approximation might be:

• DÆK-et er FLADT, så vi må ikke KØ-re VI-the-re

But this is only a guide. Danish pronunciation is less phonetic than the spelling may suggest, so listening to native audio is especially helpful here.