Fejlsøgningen begynder i dag.

Because -en is the definite article attached to the noun.

• fejlsøgning = troubleshooting / debugging
• fejlsøgningen = the troubleshooting / the debugging

In Danish, the definite article is often added to the end of the noun instead of being a separate word like the in English.

Compare:

• en fejlsøgning = a troubleshooting process
• fejlsøgningen = the troubleshooting process

So in this sentence, fejlsøgningen refers to a specific troubleshooting process.

It is a compound noun, which is extremely common in Danish.

It is made from:

• fejl = error, fault, mistake
• søgning = searching

Together, fejlsøgning literally suggests something like error-searching, which is why it means troubleshooting or debugging.

Danish often builds long nouns this way, just like German does.

Because the infinitive verb is at begynde = to begin, and its present tense is begynder.

This is just the normal conjugated form:

• at begynde = to begin
• begynder = begins / is beginning

So:

• Fejlsøgningen begynder i dag = The troubleshooting begins today

This spelling has to be learned as part of the verb. It is not formed from English-style rules.

It can mean either, depending on context.

In Danish, the present tense often covers both:

• begins
• is beginning

So Fejlsøgningen begynder i dag could be understood as:

• The troubleshooting begins today
• The troubleshooting is beginning today

In many contexts, English prefers the simple present here: begins today.

This is the normal Danish word order for a basic statement:

subject + verb + time expression

So here:

• Fejlsøgningen = subject
• begynder = verb
• i dag = time expression

This is similar to English:

• The troubleshooting begins today

Danish is a verb-second (V2) language, which means the finite verb normally comes in the second position in main clauses. In this sentence, the subject comes first, so the verb follows it.

Yes, absolutely.

That sentence is also correct:

• I dag begynder fejlsøgningen = Today, the troubleshooting begins

This happens because Danish is a V2 language. If you move i dag to the front, the verb must still stay in second position:

• I dag = first position
• begynder = second position
• fejlsøgningen = after the verb

So you cannot say:

• I dag fejlsøgningen begynder ❌

Because Danish normally uses i dag for today.

This is a fixed expression:

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

Even though i often means in, you should learn i dag as a whole expression meaning today.

Here it is being used as a specific event or process, so it behaves like a countable noun in Danish.

You can have:

• en fejlsøgning = a troubleshooting session/process
• fejlsøgningen = the troubleshooting session/process

But depending on context, it can also feel more like an activity, similar to English troubleshooting. Danish often allows this kind of noun to refer either to:

• a general activity, or
• a specific instance of that activity

In this sentence, the definite form strongly suggests a specific troubleshooting process.

A rough learner-friendly guide is:

fyle-SUHNG-ning-en

A few important notes:

• fejl sounds roughly like file in English, but not exactly
• ø in søg- is a vowel English does not really have
• the g in søgning is not pronounced like a hard English g in go
• Danish pronunciation is often much softer and less fully pronounced than the spelling suggests

If you want to say it more naturally, it is best to listen to native audio, because Danish pronunciation is hard to predict from spelling alone.

Because Danish usually adds the to the end of the noun.

So instead of:

• the troubleshooting

Danish says:

• fejlsøgningen

This is called the postposed definite article.

Very common examples:

• en bil = a car

• bilen = the car

• et hus = a house
• huset = the house

So fejlsøgningen works the same way.

Yes, in many contexts it could.

The best English translation depends on context:

• troubleshooting if you are finding the cause of a problem in general
• debugging if the context is software or programming
• sometimes fault-finding in technical contexts

So the Danish word is fairly broad. If this sentence comes from IT or programming, The debugging begins today could be a natural translation. If it is about machines, devices, or systems more generally, The troubleshooting begins today may fit better.