Barna må lære å ta vare på seg selv.

Barna means the children.

It is the definite plural form of barn:

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

In Bokmål, barna is a very common definite plural form. You may also see barnene, which is also correct, but barna is usually the more natural everyday form.

Må usually means must, have to, or need to, depending on context.

So Barna må lære ... can be understood as:

• The children must learn ...
• The children have to learn ...
• The children need to learn ...

In many contexts, English need to sounds more natural than must, even though Norwegian still uses må.

Because må is a modal verb. After modal verbs in Norwegian, you normally use the infinitive without å.

So:

• må lære = must learn
• kan komme = can come
• vil spise = will / want to eat

But lære å ta vare på ... uses å because lære å + infinitive means learn to do something.

So the structure is:

• må lære = must learn
• lære å ta vare på ... = learn to take care of ...

Yes. That is something that often surprises English speakers.

Lære can mean:

• learn
• teach

The meaning depends on the structure.

In this sentence:

• Barna må lære å ta vare på seg selv
• The children must learn to take care of themselves

Here it clearly means learn, because of lære å + verb.

Compare:

• Barna lærer norsk = The children learn Norwegian
• Læreren lærer barna norsk = The teacher teaches the children Norwegian

Ta vare på is a fixed expression meaning:

• take care of
• look after
• look after well
• sometimes protect or care for

So ta vare på seg selv means take care of oneself / themselves.

You should learn ta vare på as one unit, because the meaning is idiomatic. It is not something you usually translate word by word.

Because seg is the reflexive pronoun. It is used when the object refers back to the subject.

Here, the subject is barna and they are taking care of themselves, not some other people. So Norwegian uses seg:

• Barna må ta vare på seg selv = The children must take care of themselves

If you used dem, it would normally mean them as a separate group, not the same people as the subject.

So:

• seg selv = themselves, referring back to the subject
• dem selv would sound wrong here in standard Norwegian

Seg alone is possible in many contexts, but selv adds emphasis.

So:

• ta vare på seg = take care of oneself / themselves
• ta vare på seg selv = take care of oneself / themselves, with extra emphasis on self

In this sentence, seg selv sounds very natural because the idea is that the children should become able to manage and care for themselves.

No. Seg is used for both singular and plural in the third person when it is reflexive.

So you can have:

• Hun vasker seg = She washes herself
• De vasker seg = They wash themselves

That is why barna can still take seg selv, even though barna is plural.

The sentence is built like this:

• Barna = subject
• må = finite verb
• lære = infinitive
• å ta vare på seg selv = infinitive phrase

So literally:

• Barna | må | lære | å ta vare på seg selv

A useful point is that the finite verb is må, and it comes in the normal second position of a Norwegian main clause.

Yes.

There is a small difference:

• Barna må lære å ta vare på seg selv = the children must learn to take care of themselves
• Barn må lære å ta vare på seg selv = children must learn to take care of themselves

So:

• barna sounds like specific children, or children already known from the context
• barn sounds more general, like a statement about children in general

No. It can be broader than that.

It can include:

• staying safe
• managing on one’s own
• being responsible
• looking after one’s health
• handling everyday life

So in this sentence, it often suggests something like becoming independent enough to look after themselves, not just washing, eating, or dressing.