Hov, røgalarmen virker ikke.

Hov is an interjection. It is something like oh, whoops, hey, or hang on in English, depending on tone and situation.

In this sentence, it signals sudden realization or surprise:

• Hov, røgalarmen virker ikke. = Oh, the smoke alarm isn’t working.

It is very common in spoken, informal Danish.

Because -en is the definite ending for many common-gender nouns in Danish.

• en røgalarm = a smoke alarm
• røgalarmen = the smoke alarm

So røgalarmen is one word meaning the smoke alarm.

Danish forms compound nouns very often, just like German, and more consistently than English.

• røg = smoke
• alarm = alarm
• røgalarm = smoke alarm

Then the definite form becomes:

• røgalarmen = the smoke alarm

This is completely normal in Danish: one combined noun rather than two separate words.

Virker is the present tense of virke.

In this sentence, virke means to work, to function, or to operate:

• Røgalarmen virker ikke. = The smoke alarm doesn’t work / isn’t working.

Be aware that virke can also mean seem/appear in other contexts:

• Det virker mærkeligt. = That seems strange.

So the meaning depends on context.

Because in a normal Danish main clause, the negation ikke usually comes after the finite verb.

Pattern:

• Subject + verb + ikke

So:

• Røgalarmen virker ikke.

This is different from English, which usually needs do/does not:

• The smoke alarm does not work.

Danish does not need an extra do here.

Not exactly.

• virker ikke means doesn’t work / isn’t functioning
• går ikke i gang or other expressions might be used for doesn’t go off / doesn’t start / isn’t triggered, depending on context

So Røgalarmen virker ikke suggests the device itself is not functioning properly, not just that it failed to sound in one moment.

Because hov is a separate interjection, and in writing it is commonly set off with a comma.

So:

• Hov, røgalarmen virker ikke.

The comma helps show a pause, just like in English:

• Oh, the smoke alarm isn’t working.

It is informal to neutral everyday Danish.

The part that makes it especially informal is hov. Without it, the sentence becomes more neutral:

• Røgalarmen virker ikke. = The smoke alarm isn’t working.

So you could use the full sentence in speech or casual writing, but in formal writing you would probably leave out hov.

A rough guide is:

• røg: the vowel ø is somewhat like the vowel in French deux or German schön, if you know those
• alarm sounds a lot like English alarm, but with Danish pronunciation
• -en at the end is the definite ending

A rough English-friendly approximation might be:

• RURG-a-lahr-men
  But that is only approximate.

The hardest part for many English speakers is ø in røg.

Sometimes, but it is not exactly the same thing.

• røgalarm = smoke alarm
• brandalarm = fire alarm

A røgalarm is specifically the device that detects smoke.
A brandalarm can be broader and may refer to a fire alarm system or fire alarm generally.

So if you mean the small detector in a home, røgalarm is the best choice.

It has two parts:

1. Hov

   • an interjection

2. røgalarmen virker ikke

   • røgalarmen = subject
   • virker = finite verb
   • ikke = negation

So the core clause is:

• Subject + verb + negation

That is a very common Danish sentence pattern.

Yes, absolutely.

• Hov, røgalarmen virker ikke. = Oh, the smoke alarm isn’t working.
• Røgalarmen virker ikke. = The smoke alarm isn’t working.

The second version is more straightforward and neutral.
The first version adds surprise or sudden notice.