De oppdrar barna sammen.

Here, De means they.

It is capitalized simply because it is the first word in the sentence. If it appeared later in the sentence, it would normally be written de.

A useful extra note: in older or very formal Norwegian, De with a capital D can also mean a polite you, but that is not what is happening here.

The base form is å oppdra.

In this sentence, oppdrar is the present tense form:

• å oppdra = to raise / bring up
• oppdrar = raise / raises / are raising, depending on context

So De oppdrar means They raise or They are raising.

Because Norwegian does not usually form the present progressive the way English does.

English often distinguishes:

• They raise the children together
• They are raising the children together

Norwegian often uses the same present-tense form for both ideas:

• De oppdrar barna sammen

So one Norwegian sentence can cover both the simple present and the English be + -ing form.

Because barna means the children, while barn means child/children in an indefinite sense.

The noun barn is a bit special because the indefinite singular and indefinite plural look the same:

• et barn = a child
• barnet = the child
• barn = children
• barna = the children

So in this sentence, barna shows that we are talking about specific children: the children.

Because Norwegian usually expresses definiteness by adding it to the end of the noun.

So:

• barn = children
• barna = the children

In other words, the -a ending already includes the meaning of the.

A helpful comparison:

• hus = houses
• husene = the houses

When there is an adjective, Norwegian often uses both a separate determiner and a definite noun form:

• de små barna = the small children

Sammen means together, and in a normal Norwegian main clause it is very natural to place it after the object:

• De oppdrar barna sammen.

That word order sounds neutral and natural.

If you move sammen, the sentence can sound more marked or more focused:

• Sammen oppdrar de barna. = more emphasis on together

So the version you have is the most straightforward everyday word order.

No. They are different.

• oppdra (one word) = raise / bring up
• dra opp (two words) = usually pull up

So:

• De oppdrar barna = They are raising the children
• De drar opp noe = They pull something up

This is an important difference, because Norwegian has many verbs where writing one word or two words changes the meaning.

It can mean either, depending on context.

De oppdrar barna sammen can mean:

• They raise the children together (general/habitual)
• They are raising the children together (currently happening)

Norwegian present tense is often broader than English present tense, so context tells you which meaning is intended.

Sometimes, but raise or bring up is usually better here.

Å oppdra is about how children are brought up: their behavior, values, discipline, and general upbringing.

So in this sentence:

• They are raising the children together is the most natural translation.

Educate in English often sounds more like school teaching, while oppdra is broader and more about upbringing.