De skal stille ut maleriene.

At the beginning of a sentence, De is capitalized automatically, so it does not by itself prove that it means formal you.

In modern Norwegian, de usually means they.
There is also an older/formal De meaning you, but that is much less common today.

So the meaning depends on context, not just the spelling at the start of the sentence.

Skal is the present tense of skulle and is very often used with another verb to talk about:

• a plan
• something expected to happen
• something someone is going to do
• sometimes obligation

In this sentence, it most naturally means something like are going to or will.

So the structure is:

• De = subject
• skal = modal verb
• stille ut = main verb phrase

Because skal is a modal verb, and after modal verbs Norwegian normally uses the infinitive without å.

So you get:

• De skal stille ut maleriene.

not

• De skal å stille ut maleriene.

This is similar to English:

• They will exhibit not
• They will to exhibit

Other common modal verbs that work the same way are:

• kan
• må
• vil
• bør

Stille ut is a phrasal/particle verb.
The meaning is not just the sum of stille + ut word for word.

Here, å stille ut means:

• to exhibit
• to display

This is very common in Norwegian: a verb plus a small particle such as ut, opp, inn, av, and so on can create a new meaning.

So even if you know stille from other contexts, stille ut should be learned as a unit.

Because ut is the particle that belongs to the verb stille ut.

In the infinitive form, the verb is:

• å stille ut

In this sentence, it stays together after the modal:

• skal stille ut

Then the object comes after that:

• maleriene

So:

• De skal stille ut maleriene.

This is the normal word order.

Maleriene means the paintings.

It is the definite plural form of maleri (painting).

The forms are:

• et maleri = a painting
• maleriet = the painting
• malerier = paintings
• maleriene = the paintings

So the ending -ene here marks definite plural.

This is a standard main-clause word order in Norwegian:

• De = subject
• skal = finite verb
• stille ut = infinitive/main verb
• maleriene = object

So the pattern is roughly:

Subject + finite verb + infinitive + object

That is very common when a modal verb is used.

Yes, utstille exists and can also mean exhibit/display.

However, stille ut is very common and natural. In many everyday contexts, it may sound more idiomatic than utstille.

So both can be possible, but stille ut is an excellent form to learn and use.

No. Stille can have different meanings depending on the context, and when combined with a particle, the meaning can change a lot.

For example, stille ut means to exhibit/display, which is not the same as every other use of stille.

That is why it is best to learn stille ut as one vocabulary item, not by translating stille alone.

In a yes/no question, Norwegian usually puts the finite verb first:

• Skal de stille ut maleriene?

That means Are they going to exhibit the paintings?

So the verb skal moves before the subject de.