Nedkjølingen er farlig, og fremmedlegemet blokkerer luftveiene.

Those endings mark definiteness in Norwegian.

• nedkjøling → nedkjølingen = the hypothermia / the cooling
• fremmedlegeme → fremmedlegemet = the foreign body
• luftvei → luftveiene = the airways

So instead of putting a separate word like the in front, Norwegian often adds the definite ending to the noun itself.

• -en often marks definite singular for common-gender nouns
• -et often marks definite singular for neuter nouns
• -ene often marks definite plural

The basic forms are:

• en nedkjøling = a cooling, hypothermia
• et fremmedlegeme = a foreign body
• en luftvei = an airway

In the sentence, they appear in definite form:

• nedkjølingen
• fremmedlegemet
• luftveiene

This is the form you use when talking about a specific thing, not just the general concept.

Because Norwegian usually puts the at the end of the noun as a suffix.

Compare:

• en luftvei = an airway

• luftveien = the airway

• et fremmedlegeme = a foreign body
• fremmedlegemet = the foreign body

English uses a separate article; Norwegian usually uses an ending.

A separate article like den/det/de is mainly added when there is an adjective:

• luftveiene = the airways
• de øvre luftveiene = the upper airways

Because it refers to the person’s specific airways, not to airways in general.

• luftveier = airways (indefinite/general)
• luftveiene = the airways (specific)

In medical or anatomical language, definite forms are very common when talking about parts of the body or a known condition.

Also, airways is naturally plural because it refers to the airway passages as a system, not just one single tube.

Fremmedlegeme is a medical term meaning foreign body.

It is made of:

• fremmed = foreign, strange
• legeme = body

So et fremmedlegeme is something that should not be there, such as food, an object, or another substance inside the body.

In this sentence, it is something blocking the airways.

Blokkerer is the present tense of å blokkere = to block.

So:

• å blokkere = to block
• blokkerer = blocks / is blocking

Norwegian verbs are much simpler than English verbs in this way: the verb form does not change for different persons.

• jeg blokkerer = I block
• du blokkerer = you block
• han/hun blokkerer = he/she blocks
• de blokkerer = they block

The same is true for er in the first clause:

• Nedkjølingen er farlig = The hypothermia is dangerous

Here farlig is used after er, so it is a predicate adjective:

• Nedkjølingen er farlig = The hypothermia is dangerous

With a singular subject, this basic form is normal.

A useful comparison:

• Situasjonen er farlig = The situation is dangerous
• Situasjonene er farlige = The situations are dangerous

So the main contrast to remember is:

• singular: farlig
• plural: farlige

Yes, but the meaning shifts slightly.

• Nedkjøling er farlig = Hypothermia/cooling is dangerous in general
• Nedkjølingen er farlig = The hypothermia / this cooling is dangerous, referring to a specific case or the condition already being discussed

So the version in your sentence sounds more like a concrete medical situation.

Because og joins two complete clauses, each with its own subject and finite verb:

1. Nedkjølingen er farlig
2. fremmedlegemet blokkerer luftveiene

In Norwegian, it is standard to use a comma between coordinated main clauses like this.

So the comma helps show that these are two full statements linked together.

Not here. Each part is a normal main clause.

• Nedkjølingen er farlig
• fremmedlegemet blokkerer luftveiene

In both clauses, the finite verb is in the usual main-clause position. Since the subject comes first, the order looks like:

• subject + verb + rest

So:

• fremmedlegemet = subject
• blokkerer = verb
• luftveiene = object

Yes. Norwegian makes heavy use of compound nouns, and this sentence is a good example.

You can break them down like this:

• nedkjøling = ned
  • kjøling
    • roughly cooling down
• fremmedlegeme
  • fremmed = foreign
  • legeme = body
• luftvei
  • luft = air
  • vei = way/path

This is very common in Norwegian, especially in technical and medical vocabulary. Learning to spot the parts of a compound word makes long words much easier to understand.