Barnet stirrer på heksen.

Because Norwegian usually puts the definite article onto the end of the noun instead of using a separate word before it.

So:

• barn = child
• barnet = the child
• heks = witch
• heksen = the witch

That is why Barnet stirrer på heksen already includes the idea of the twice, even though there is no separate word like English the.

The endings are different because the nouns belong to different grammatical genders.

• et barn → barnet
  barn is a neuter noun.
• en heks / ei heks → heksen / heksa
  heks can be treated as common gender or feminine in Bokmål.

In this sentence, the writer uses heksen, which is a very normal Bokmål form. So the different endings do not mean different kinds of definiteness; they reflect different noun genders and patterns.

Because stirrer is the present tense form of the verb å stirre.

• å stirre = to stare
• stirrer = stares / is staring

So:

• Barnet stirrer = The child stares / is staring

This is the normal present-tense form in Bokmål.

Because the infinitive verb is å stirre, and the present-tense form is built as stirrer.

A useful way to think of it is:

• infinitive: stirre
• present tense: stirrer

Since the verb already has an r in the stem, the present-tense spelling ends up with rr. This is normal and not something special about this sentence.

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

You say:

• jeg stirrer = I stare / am staring
• du stirrer = you stare / are staring
• barnet stirrer = the child stares / is staring
• barna stirrer = the children stare / are staring

So stirrer stays the same.

Because å stirre på is the normal Norwegian pattern for to stare at someone or something.

So:

• stirre på noen = stare at someone
• stirre på noe = stare at something

In English, the verb usually goes with at. In Norwegian, the matching preposition here is usually på.

They are related, but stirre på is much stronger.

• se på = look at / watch
• stirre på = stare at

So Barnet stirrer på heksen suggests that the child is looking very fixedly, intensely, or for a noticeable amount of time. It sounds stronger than just Barnet ser på heksen.

This is the normal word order for a simple statement:

• Barnet = subject
• stirrer = verb
• på heksen = prepositional phrase

So it follows the basic pattern subject + verb + rest.

More generally, Norwegian main clauses follow the V2 rule, which means the finite verb normally comes in the second position. In this sentence, the subject comes first, so the verb comes right after it.

For example:

• Barnet stirrer på heksen.
• Nå stirrer barnet på heksen.

In both cases, the finite verb stirrer is in second position.

Yes. Because both nouns are definite:

• barnet = the child
• heksen = the witch

That usually means the listener or reader is expected to know which child and which witch are being talked about, or the context has already made them identifiable.

If you wanted it to be indefinite, you would say:

• Et barn stirrer på en heks. = A child is staring at a witch.

A rough learner-friendly pronunciation is:

BAR-ne(t) STIR-rer po HEK-sen

A few notes:

• barnet: the final -t is often weak or not clearly pronounced in everyday speech
• stirrer: the rr is normal spelling; pronunciation varies by dialect
• på: has a long vowel
• heksen: stress is on the first syllable

Pronunciation varies across Norway, so exact sounds can differ by dialect, but this rough guide will help you recognize the words.