Verdenskrigen endret verden.

Because Norwegian usually writes compound nouns as one word.

So verdenskrigen is built like this:

• verdenskrig = world war
• verdenskrigen = the world war

This is very typical in Norwegian. Where English often uses two words, Norwegian often makes a compound:

• verdenskrig = world war
• skolebok = schoolbook / school book
• sommerferie = summer holiday

So a native English speaker may want to split it up, but in Norwegian that would normally be wrong.

That -s- is a very common linking element in Norwegian compounds.

Here the first part comes from verden or historically verdens, and it connects to krig:

• verden = world
• verdenskrig = world war

You do not need to think of it as a separate word. It is just part of how many compounds are formed.

You see the same pattern in other words too:

• verdensmester = world champion
• verdensdel = continent, literally part of the world

So for learners, the important point is: this s is normal and common in compounds.

Because Norwegian usually shows definiteness by adding it to the end of the noun.

So instead of a separate article like English the, Norwegian often uses a suffix:

• krig = war

• krigen = the war

• verden = the world / world, depending on usage
• verdenen = the world

In verdenskrigen, the -en at the end means the.

So the sentence does not need a separate word like English the before verdenskrigen.

Endret is the past tense of å endre.

• å endre = to change
• endrer = changes / is changing
• endret = changed

So in this sentence, endret tells you that the action happened in the past.

A useful thing to know is that endret is also the past participle form, so the same spelling can appear in different structures. But here, standing alone after the subject, it is understood as the simple past tense.

Both forms exist, but verden is very common and natural.

You can think of it like this:

• verden = the usual everyday form
• verdenen = a fuller form, sometimes more formal, literary, or emphatic

In many contexts, Norwegian prefers verden where English learners might expect a longer definite form.

So Verdenskrigen endret verden sounds natural.
You may also see verdenen in other sentences, but verden is extremely common.

No. This is a very basic subject–verb–object sentence:

• Verdenskrigen = subject
• endret = verb
• verden = object

So the structure is very straightforward.

This is actually helpful for English speakers, because the order matches normal English word order quite closely.

Usually yes: it sounds like the World War, meaning a specific war already understood from context.

However, in modern Norwegian, people often prefer to be more specific:

• første verdenskrig = the First World War
• andre verdenskrig = the Second World War

So Verdenskrigen by itself may sound historical, literary, or context-dependent. It can work if the reader already knows which war is meant.

It is capitalized only because it is the first word of the sentence.

In Norwegian, common nouns are not normally capitalized the way they are in German. So in the middle of a sentence, it would be:

• verdenskrigen

The same goes for verden and krig: they are not capitalized unless they begin a sentence.

A rough pronunciation guide is:

VER-dens-kree-gen EN-dret VER-den

A few helpful notes:

• v is pronounced like English v
• e in verden is shorter than many English speakers expect
• kr in krigen is pronounced clearly; the k is not silent
• the r sound may be stronger or more tapped than in English, depending on dialect
• endret has two syllables: EN-dret

You do not need perfect pronunciation right away, but it helps to remember that Norwegian spelling is often more regular than English spelling.

Not normally.

Verdenskrig without the definite ending means world war in a more general or indefinite sense, not the world war.

So:

• verdenskrig = world war
• verdenskrigen = the world war

In this sentence, the definite form is the natural choice because it refers to a specific war, not the general concept of world war.