De undersøker materialet.

In modern Norwegian, de normally means they and is usually written with a lowercase d.

A capitalized De can be used as a formal/polite form of you, similar to older English You in very polite writing. This usage is now quite old-fashioned and uncommon in everyday Norwegian, but you may still see it in formal, older, or especially polite contexts.

So depending on context, De undersøker materialet could be read as:

• They examine/are examining the material
• You examine/are examining the material (formal)

Without context, modern learners will most often treat de as they.

The base form is å undersøke, which means to examine, to investigate, or to inspect.

Here are some related forms:

• å undersøke = to examine / investigate
• undersøker = examine(s) / is examining / are examining
• undersøkte = examined / was examining / were examining
• har undersøkt = have/has examined

Undersøker is in the present tense.

In Norwegian, the present tense often covers both:

• English simple present: examine
• English present progressive: are examining

So De undersøker materialet can mean either:

• They examine the material
• They are examining the material

The exact English translation depends on context.

Because Norwegian usually puts the definite article at the end of the noun as a suffix.

So:

• et materiale = a material
• materialet = the material

The ending -et is the definite ending here.

This is very common in Norwegian:

• en bil = a car → bilen = the car
• et hus = a house → huset = the house
• et materiale = a material → materialet = the material

Because materiale is a neuter noun in Norwegian.

Norwegian nouns have grammatical gender. In Bokmål, the main genders are:

• en-words
• et-words
• sometimes ei-words

Since materiale is neuter, it takes:

• et materiale = a material
• materialet = the material

If it were a common-gender noun, you would usually get -en instead.

Yes. This is the normal word order for a simple main clause:

• Subject + verb + object

So:

• De = subject
• undersøker = verb
• materialet = object

This is very similar to basic English word order:

• They examine the material

No. Norwegian verbs do not change for person the way English verbs sometimes do.

For example, Norwegian uses the same present-tense form:

• jeg undersøker = I examine / am examining
• du undersøker = you examine / are examining
• han undersøker = he examines / is examining
• vi undersøker = we examine / are examining
• de undersøker = they examine / are examining

So you do not need different verb endings for I, you, he, they, and so on.

A rough guide is:

UN-der-suh-ker

A few pronunciation notes:

• u in under- is not exactly like English oo, but that rough approximation can help at first.
• ø is a vowel that does not exist in standard English. It is somewhat similar to the vowel in French deux or German schön.
• The r is pronounced, though the exact sound varies by dialect.
• The stress is usually on the first syllable: UNdersøker.

If you are just starting, the most important thing is to notice that ø is its own vowel and should not be pronounced like plain o.

It depends on context. Materialet can refer to different kinds of material or data, for example:

• physical material
• written material
• research material
• source material
• evidence/data being examined

So the sentence could be used in a lab, a classroom, an office, or an investigation, depending on what materialet refers to.

Yes, but it would mean something different.

• De undersøker materialet = They are examining the material
• De undersøker materiale = They are examining material / materials in a more general or indefinite sense

So materialet points to a specific material already known from the context, while materiale is more general or indefinite.

You usually know from context.

In modern Norwegian, de with a lowercase d normally means they. A capitalized De may be a formal you, but that is much less common today.

So in most modern texts:

• de = they

If you see De capitalized, ask:

• Is this an older text?
• Is it very formal or especially polite?
• Does the surrounding context address someone directly?

That usually tells you whether it means they or formal you.