Bursdagsbarnet kommer i morgen.

It is a compound noun:

• bursdag = birthday
• barn = child
• -et = the definite ending for a neuter noun

So bursdagsbarnet literally means the birthday child, but in normal use it means the person whose birthday it is.

In Norwegian, the definite article is often attached to the end of the noun instead of standing as a separate word.

So:

• et barn = a child
• barnet = the child

That is why you get bursdagsbarnet, not a separate word like English the birthday child.

Not necessarily. Even though barn literally means child, bursdagsbarnet is often used playfully for anyone whose birthday it is, including adults.

So it can sound warm, cheerful, or slightly cute rather than strictly literal.

That -s- is a linking sound often used in Norwegian compounds.

Here the compound is built like this:

• bursdag
  • s
    • barnet

This linking s does not have a separate meaning by itself. It just helps form the compound in a natural way. Norwegian has many compounds like this.

Kommer is the present tense of å komme = to come.

Even though the sentence refers to the future, Norwegian often uses the present tense when the time is clear from the context.

Here, i morgen already tells you the event is in the future, so kommer works naturally:

• Bursdagsbarnet kommer i morgen.

This is very similar to English sentences like She arrives tomorrow.

It can correspond to either, depending on context.

Norwegian present tense is often less specific than English about the difference between:

• comes
• is coming

So kommer can cover both ideas. In this sentence, English might translate it as either comes tomorrow or is coming tomorrow, depending on the situation.

I morgen means tomorrow.

It is a time expression, and it tells you when the action happens. Even though i often means in, you should learn i morgen as a fixed expression meaning tomorrow.

Yes. Norwegian often allows that.

You can say:

• Bursdagsbarnet kommer i morgen.
• I morgen kommer bursdagsbarnet.

Both are correct. The difference is mainly emphasis:

• starting with bursdagsbarnet focuses more on the person
• starting with i morgen focuses more on the time

Because Norwegian follows the verb-second rule in main clauses.

That means the finite verb usually comes in the second position. So if you move i morgen to the front, the verb kommer must come right after it:

• I morgen kommer bursdagsbarnet.

You do not say:

• I morgen bursdagsbarnet kommer.

That sounds wrong in Norwegian main-clause word order.

Barn is a neuter noun.

That matters because neuter nouns take:

• et in the indefinite form
• -et in the definite singular

So:

• et barn = a child
• barnet = the child

That same neuter ending appears in bursdagsbarnet.

A rough guide for an English speaker would be something like:

BURS-dahgs-bahr-net

A few notes:

• u in burs- is not exactly like English u
• dags has a clear gs sound
• barnet ends with -neht, not with a silent t

Pronunciation varies somewhat by dialect, but that rough shape will help you recognize and say the word.

Yes. It is a very standard main clause:

• Bursdagsbarnet = subject
• kommer = verb
• i morgen = time expression

So the pattern is:

subject + verb + time

That is one of the most basic and common sentence patterns in Norwegian.