Nødreparationen efter rørbruddet begynder i dag.

Because Danish, like English, often forms compound nouns by joining words together, but Danish does this even more consistently.

• nød = emergency
• reparation = repair
• nødreparation = emergency repair
• nødreparationen = the emergency repair

So Danish prefers one combined noun where English might sometimes also use two words in explanation.

It is the definite article attached to the noun.

In Danish, instead of usually putting a separate word like the before the noun, you often add the definiteness to the end:

• en reparation = a repair
• reparationen = the repair

Since nødreparation is a common-gender noun, its definite ending is -en.

Because brud is a neuter noun in Danish.

• et brud = a break / rupture
• bruddet = the break / the rupture

When brud becomes part of the compound rørbrud:

• et rørbrud = a pipe rupture / burst pipe incident
• rørbruddet = the pipe rupture / the burst

So the definite ending is -et, not -en.

Literally, it is:

• rør = pipe
• brud = break, rupture

So rørbrud means something like pipe break, pipe rupture, or burst pipe incident.

In natural English, you would often translate it as:

• the pipe burst
• the burst pipe
• the pipe rupture

The best English version depends on context, but the Danish noun itself is a standard compact way to express the event.

Danish often uses a noun phrase where English might prefer a clause.

So instead of saying something equivalent to after the pipe broke, Danish can simply say:

• efter rørbruddet = after the pipe rupture / after the burst pipe incident

This is very normal and idiomatic in Danish, especially in formal, written, or news-like language.

It means after the pipe burst / following the pipe rupture.

Grammatically, it is a prepositional phrase introduced by efter = after.

In this sentence, it most naturally connects to nødreparationen:

• Nødreparationen efter rørbruddet = the emergency repair after the pipe burst

So the subject is not just nødreparationen, but the larger noun phrase nødreparationen efter rørbruddet.

Because Danish main clauses follow the V2 rule: the finite verb normally comes in the second position.

Here, the first element is the whole subject:

• Nødreparationen efter rørbruddet = position 1

Then comes the finite verb:

• begynder = position 2

Then the time expression:

• i dag

So the structure is:

• [Subject] [Verb] [Time]

You could also move the time expression to the front:

• I dag begynder nødreparationen efter rørbruddet.

That is also correct, and then begynder still stays in second position.

Both begynder and starter can mean begins/starts, but begynde is often the more neutral and common choice for events, processes, or activities.

• arbejdet begynder = the work begins
• mødet begynder = the meeting begins

starte is also possible in many contexts, but begynder sounds very natural here.

Because Danish usually marks definiteness by adding an ending to the noun itself.

So instead of separate the:

• reparationen = the repair
• rørbruddet = the pipe rupture

This is one of the biggest differences from English.

However, Danish can also use a separate definite word in some cases, especially with adjectives:

• reparationen = the repair
• den store reparation = the big repair

So in your sentence, no separate the is needed.

Because i dag is the fixed Danish expression for today.

It works as an adverbial expression of time:

• i dag = today
• i morgen = tomorrow
• i går = yesterday

You simply learn these as standard expressions. In this sentence, i dag tells you when the emergency repair begins.

Yes, absolutely.

Both are correct:

• Nødreparationen efter rørbruddet begynder i dag.
• I dag begynder nødreparationen efter rørbruddet.

The difference is mainly focus:

• Starting with Nødreparationen... focuses on the repair itself.
• Starting with I dag... highlights today.

In both versions, Danish keeps the finite verb in second position.

Yes, it sounds natural, especially in a news, official, or informational style.

It has a slightly formal/informative tone because of words like:

• nødreparation
• rørbrud

In everyday speech, someone might choose a simpler wording depending on context, but this sentence is completely normal and idiomatic Danish.