Vi må teipe igjen flytteesken med pakketeipen.

Because må is a modal verb, and modal verbs in Norwegian normally take a bare infinitive after them.

So:

• Vi må teipe = We must tape / We have to tape

Not:

• Vi må å teipe

This works the same way with other modal verbs too:

• Vi kan teipe
• Vi skal teipe
• Vi vil teipe

Here teipe igjen means tape shut or seal with tape.

The verb teipe means to tape, and igjen here adds the idea of closing something up. So it is not just putting tape on something in general; it specifically means taping it closed.

This use of igjen is common in Norwegian:

• lukke igjen døra = close the door
• smelle igjen vinduet = slam the window shut
• teipe igjen esken = tape the box shut

No. In this sentence, igjen means something like shut or closed up, not again.

That is a very common source of confusion, because igjen can also mean again in other contexts:

• Kan du si det igjen? = Can you say that again?
• Han kom igjen i går. = He came again yesterday.

But in teipe igjen flytteesken, the meaning is clearly tape the moving box shut.

Putting igjen right after teipe helps show that teipe igjen belongs together as a unit meaning tape shut.

If you move igjen later in the sentence, it can sound more like again:

• teipe igjen flytteesken = tape the moving box shut
• teipe flytteesken igjen = could easily be understood as tape the moving box again

So the word order here helps avoid ambiguity.

Because Norwegian normally writes compound nouns as one word.

flytteesken breaks down like this:

• flytteeske = moving box
• flytteesken = the moving box

And flytteeske itself is a compound:

• flytte = move / moving
• eske = box

So Norwegian prefers one combined word where English often uses two words.

Because the parts come together as:

• flytte
• eske

When they combine, both e letters remain:

• flytte + eske = flytteeske
• definite form: flytteesken

This is normal in Norwegian compounds. The spelling may look unusual at first, but it is not a mistake.

The ending -en is the singular definite ending for many common-gender nouns. It corresponds to English the.

So:

• en flytteeske = a moving box
• flytteesken = the moving box

And:

• en pakketeip = a packing tape / a roll of packing tape
• pakketeipen = the packing tape

Norwegian often puts the definite article at the end of the noun instead of using a separate word like English the.

Because the sentence sounds like it is talking about a specific box and a specific tape that both speaker and listener already know about.

So:

• flytteesken = the moving box
• pakketeipen = the packing tape

This is very natural in context, for example if there is one box in front of you and one roll of packing tape nearby.

If you wanted a more general or less specific meaning, you might change the nouns:

• Vi må teipe igjen en flytteeske med pakketeip. = We need to tape up a moving box with packing tape.

Here med means with, in the sense of using something as a tool or material.

So med pakketeipen means:

• with the packing tape
• using the packing tape

This is a very common use of med in Norwegian:

• kutte med kniv = cut with a knife
• skrive med blyant = write with a pencil
• teipe igjen esken med pakketeip = tape the box shut with packing tape

pakketeip means packing tape, and it is also a compound noun, so Norwegian writes it as one word.

It consists of:

• pakke = pack / package
• teip = tape

Together:

• pakketeip = packing tape
• pakketeipen = the packing tape

Again, this is typical Norwegian compound spelling.

Yes. Teipe is a normal and common verb in modern Norwegian.

It comes from the noun teip = tape, so:

• teip = tape
• å teipe = to tape

This spelling is useful because å tape already means to lose in Norwegian:

• å tape kampen = to lose the match

So teipe and tape are different words.

A flytteeske is a moving box, meaning the kind of cardboard box used when moving house or packing things for transport or storage.

So eske by itself means box, and flytteeske is a more specific type of box.

In everyday use, it usually suggests the standard cardboard box people use during a move.

You could, but it does not mean exactly the same thing.

• Vi må teipe igjen flytteesken med pakketeipen = We need to tape the moving box shut
• Vi må teipe flytteesken med pakketeipen = We need to tape the moving box with the packing tape

The second version just says you are putting tape on the box. The first version clearly says you are sealing it closed. So igjen is important here.