Jeg må levere tilbake boken i morgen.

Because må is a modal verb. In Norwegian, modal verbs like må often work directly with an infinitive, without å.

• Jeg må levere ... = I must/have to deliver/return ...
• Not: Jeg må å levere ...

Common modal verbs that behave like this include:

• kan = can
• skal = shall / will / am going to
• vil = will / want to
• må = must / have to
• bør = should

So after må, the infinitive comes without å.

Må means must or have to. It expresses necessity or obligation.

In this sentence, it sounds like:

• I have to return the book tomorrow
• I must return the book tomorrow

In everyday English, have to is often the most natural translation, even though må is also related to must.

Because levere tilbake is a common Norwegian expression meaning to return something in the sense of give it back.

Literally:

• levere = deliver / hand in
• tilbake = back

So:

• levere tilbake boken = return the book / give the book back

This is similar to English phrasal-style expressions like give back.

Yes, sometimes. Norwegian often allows a bit of flexibility with particles like tilbake.

You may hear:

• Jeg må levere tilbake boken i morgen.
• Jeg må levere boken tilbake i morgen.

Both are natural. The second one is often especially common in speech.

So tilbake can appear:

• right after the verb
• after the object

Both patterns are useful to recognize.

Because boken means the book, while en bok means a book.

Norwegian usually puts the definite article at the end of the noun:

• bok = book
• en bok = a book
• boken = the book

So in this sentence, the speaker is referring to a specific book, not just any book.

Yes. In Bokmål, many feminine nouns can take either a feminine or a common-gender-style definite form, depending on style and dialect.

For bok, you may see:

• boken
• boka

Both can mean the book.

So these are both possible:

• Jeg må levere tilbake boken i morgen.
• Jeg må levere tilbake boka i morgen.

Both are correct in Bokmål. Which one sounds more natural can depend on the speaker, region, or writing style.

I morgen means tomorrow, and time expressions often come late in a Norwegian sentence, especially in a simple main clause like this one.

So:

• Jeg må levere tilbake boken i morgen.

is a very normal word order.

But Norwegian is flexible, and you can move i morgen for emphasis:

• I morgen må jeg levere tilbake boken.

That version emphasizes tomorrow.

The structure is:

• Jeg = subject
• må = finite verb
• levere = infinitive
• tilbake boken = object phrase / verb phrase continuation
• i morgen = time expression

So the pattern is roughly:

Subject + finite verb + infinitive + object + time

This is normal in a Norwegian main clause.

Very often, yes, especially when you mean give something back physically.

For example:

• return a book to the library
• return borrowed keys
• return something to a friend

In those cases, levere tilbake is very natural.

You might also encounter:

• returnere = return

But returnere can sound more formal, more abstract, or more like a direct borrowing from international vocabulary. For everyday situations with objects, levere tilbake is often the safer and more natural choice.

Because Norwegian, like English, only includes the words that are needed.

This sentence simply says:

• I have to return the book tomorrow

It does not specify:

• to whom
• where
• exactly why

If needed, Norwegian could add that information:

• Jeg må levere tilbake boken til biblioteket i morgen.
  = I have to return the book to the library tomorrow.

So the original sentence is complete without extra details.

You would usually place ikke after the modal verb:

• Jeg må ikke levere tilbake boken i morgen.

But be careful: this can mean I must not return the book tomorrow.

If you want to say I don’t have to return the book tomorrow, Norwegian often prefers:

• Jeg trenger ikke levere tilbake boken i morgen.

That distinction is important:

• må ikke = must not
• trenger ikke = do not need to / don’t have to

In standard spoken Norwegian, jeg is often pronounced roughly like yai or yay, depending on dialect and speaking style.

A few important points:

• the written g is often not pronounced like an English hard g
• pronunciation varies a lot by region
• in casual speech, it may sound quite different from how an English speaker expects from the spelling

So even though it is written jeg, don’t expect a fully pronounced English-like yeg in normal speech.

Yes. That is also correct and natural.

Compare:

• Jeg må levere tilbake boken i morgen.
• Jeg må levere boken tilbake i morgen.

Both mean the same thing. The difference is mainly the position of tilbake.

As a learner, it is a good idea to recognize both patterns, because both are common in real Norwegian.