Sykkelskjermen er ødelagt.

Because Norwegian usually writes compound nouns as a single word.

Here, sykkelskjermen is made up of:

• sykkel = bicycle
• skjerm = screen / shield / fender, depending on context
• -en = the definite ending

So the basic noun is sykkelskjerm, and sykkelskjermen means the bicycle fender/mudguard.

The ending -en marks the noun as singular definite.

Compare:

• en sykkelskjerm = a bicycle fender
• sykkelskjermen = the bicycle fender

In Norwegian, the is often attached to the end of the noun instead of being a separate word as in English.

In Norwegian, definiteness is usually built into the noun itself.

So instead of:

• English: the bicycle fender

you often get:

• Norwegian: sykkelskjermen

However, if there is an adjective before the noun, Norwegian often uses both a separate definite word and the definite noun form:

• den ødelagte sykkelskjermen = the broken bicycle fender

This is sometimes called double definiteness.

Er is the present tense of å være = to be.

So:

• er = is / are

In this sentence, it simply links the subject and the description:

• Sykkelskjermen er ødelagt = The bicycle fender is broken

Here, ødelagt functions as an adjective-like description, meaning broken, damaged, or ruined.

Historically, it is the past participle of å ødelegge = to destroy / damage / ruin. In sentences like this, it is very common to use such forms after er:

• Døren er lukket = The door is closed
• Vinduet er knust = The window is broken
• Sykkelskjermen er ødelagt = The bicycle fender is broken

So a learner can think of ødelagt here as a description of the noun’s condition.

Because after er, the adjective/past participle does not become definite just because the noun is definite.

So even though sykkelskjermen means the bicycle fender, you still say:

• Sykkelskjermen er ødelagt

not:

• Sykkelskjermen er ødelagte

The form ødelagte is used in other situations, especially:

• before a definite plural noun: de ødelagte delene = the broken parts
• often as a plural predicate: Delene er ødelagte = The parts are broken

This is the normal Norwegian statement pattern:

• Subject + verb + complement

So:

• Sykkelskjermen = subject
• er = verb
• ødelagt = complement

If you turned it into a yes/no question, the verb would come first:

• Er sykkelskjermen ødelagt? = Is the bicycle fender broken?

No. Skjerm has a wider range of meanings than English screen.

Depending on context, it can mean things like:

• a screen
• a shield
• a cover
• a fender / mudguard

In sykkelskjerm, it refers to the part of the bicycle that blocks water and dirt from the wheel, so fender or mudguard is the natural meaning.

Yes. That would also be grammatical.

Compare:

• Sykkelskjermen er ødelagt
• Skjermen på sykkelen er ødelagt

Both mean roughly the same thing. The first version uses a compound noun, which is very natural in Norwegian. The second version is more literally the fender on the bicycle.

Norwegian often prefers compound nouns where English might use of or another structure.

The indefinite singular form is:

• en sykkelskjerm = a bicycle fender

Other useful forms are:

• en sykkelskjerm = indefinite singular
• sykkelskjermen = definite singular
• sykkelskjermer = indefinite plural
• sykkelskjermene = definite plural

These forms are very useful to memorize together.

A rough guide is:

• sykkelskjermen: the skj sounds like English sh
• er: a short air/eh-like sound, depending on dialect
• ødelagt: the ø has no exact English equivalent; it is a rounded front vowel

A very rough approximation for an English speaker might be:

• SHUK-kel-sher-men er UR-deh-lakht

But that is only approximate. The hardest sounds for many English speakers are:

• y in sykkel
• ø in ødelagt
• the Norwegian r, which varies by dialect

If you want, I can also break the whole sentence down sound by sound in a learner-friendly way.