Vi undersøker påstanden.

Because undersøker is the present tense form of the verb å undersøke (to investigate / to examine).

A very common pattern in Norwegian is:

• infinitive: å undersøke
• present tense: undersøker

So Vi undersøker påstanden means we investigate / we are investigating the claim, depending on context.

Unlike English, Norwegian usually uses the simple present form here and does not need a separate verb like are.

In Norwegian, you normally do not use a separate auxiliary like English am/is/are to make a present ongoing action.

English:

• We investigate the claim
• We are investigating the claim

Norwegian often uses the same form for both ideas:

• Vi undersøker påstanden

So the present tense alone can cover both a general present and an action happening now. The exact meaning depends on context.

Påstanden is the definite singular form of påstand.

• påstand = claim / assertion
• påstanden = the claim / the assertion

In Norwegian, definiteness is often shown by adding an ending to the noun instead of using a separate word like the.

For many masculine nouns:

• indefinite: en påstand = a claim
• definite: påstanden = the claim

So the -en ending is doing the job that the does in English.

Because Norwegian usually expresses the by attaching the definite ending directly to the noun.

So:

• påstanden = the claim

You use den påstanden only in certain situations, especially when there is an adjective or when you want extra emphasis.

For example:

• påstanden = the claim
• den viktige påstanden = the important claim
• den påstanden can also mean that claim or give special emphasis, depending on context

In your sentence, påstanden by itself is the normal and natural form.

Vi is the subject pronoun meaning we.

It is used when the speaker includes themself with one or more other people.

Examples:

• Jeg undersøker påstanden = I investigate the claim
• Vi undersøker påstanden = We investigate the claim

So vi is simply the subject of the sentence.

Yes. This is a normal Norwegian declarative main clause, and the word order is:

• Vi = subject
• undersøker = verb
• påstanden = object

So:

• Vi undersøker påstanden

This is the standard pattern for a simple statement.

Norwegian is a V2 language, which means the finite verb usually comes in the second position in main clauses. In this sentence, the subject comes first, so the verb comes right after it.

If another element comes first, the verb still stays second:

• I dag undersøker vi påstanden = Today we are investigating the claim

Notice that undersøker still comes second.

Yes, but it means something different.

• Vi undersøker påstanden = We are investigating the claim
  This refers to a specific claim already known from the context.

• Vi undersøker en påstand = We are investigating a claim
  This introduces the claim as non-specific or new information.

So the choice between påstanden and en påstand is the same kind of distinction as the claim versus a claim in English.

The letter ø is one of the extra Norwegian vowels, and it does not have an exact English equivalent.

A rough guide:

• It sounds somewhat like the vowel in French deux or German schön, if you know those.
• For English speakers, you can think of it as a rounded vowel somewhere between uh and er, but with rounded lips.

In undersøker, the ø sound appears twice.

A rough pronunciation guide for the whole word might be:

• UN-der-sø-ker

But it is best to hear it from native audio, because ø is hard to learn from spelling alone.

Yes, undersøker is a perfectly normal and useful verb, but it can sound a little more formal or precise than some everyday alternatives.

Depending on context, Norwegian might also use:

• ser på = look at / examine
• sjekker = check
• går gjennom = go through / review

But undersøker is a very good choice when you mean investigate, examine, or look into in a more serious or careful way.

So Vi undersøker påstanden sounds natural, especially in academic, journalistic, legal, or analytical contexts.

The dictionary form is å undersøke.

In Norwegian, verbs are usually listed with å, which is the infinitive marker, similar to to in English.

So:

• å undersøke = to investigate
• undersøker = investigate / investigates / am investigating / is investigating / are investigating, depending on context

When you use the verb in a sentence with a subject, you normally do not include å:

• Vi undersøker påstanden not
• Vi å undersøke påstanden

This sentence is standard Bokmål.

In Nynorsk, you would more naturally see:

• Vi undersøkjer påstanden

The difference is mainly in the verb form:

• Bokmål: undersøker
• Nynorsk: undersøkjer

Everything else in the sentence is very similar.