Reparasjonskostnaden er høy.

Because Norwegian, like English in some cases, often builds compound nouns by joining smaller words together.

Here, reparasjonskostnaden is made from:

• reparasjon = repair
• kostnad = cost
• -en = the definite ending

So the structure is:

reparasjon + s + kostnad + en

The s is a linking sound that often appears in compounds. Norwegian usually writes this as one word, not as separate words.

The ending -en marks the noun as definite singular for a common-gender noun.

So:

• en kostnad = a cost
• kostnaden = the cost

In the full compound:

• en reparasjonskostnad = a repair cost
• reparasjonskostnaden = the repair cost

This is very common in Norwegian: instead of putting a separate word like the in front, Norwegian often adds the definiteness to the end of the noun.

Because Norwegian usually expresses the by attaching an ending to the noun.

So instead of writing something like the repair cost, Norwegian says:

• reparasjonskostnaden

The definite ending already includes the idea of the.

A separate definite word such as den is only used in certain situations, for example when there is an adjective before the noun:

• den høye reparasjonskostnaden = the high repair cost

But in Reparasjonskostnaden er høy, no extra den is needed.

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

So the sentence follows a very basic pattern:

• Reparasjonskostnaden = subject
• er = is
• høy = high

This is the normal Norwegian equivalent of an English is sentence.

Because predicate adjectives in Norwegian change form depending on the noun.

Here, reparasjonskostnaden is:

• singular
• common gender
• definite

With a singular common-gender noun, the adjective stays in its basic form:

• Kostnaden er høy = The cost is high

Compare:

• Huset er høyt = The house is tall/high-ish in form, or high
• Kostnadene er høye = The costs are high

So høy is correct because reparasjonskostnaden is singular common gender.

In Norwegian compounds, the last part is usually the main noun.

So in reparasjonskostnaden:

• kostnad is the core noun = cost
• reparasjons- tells you what kind of cost it is = repair-related

This is similar to English compounds like car door or school bus, where the last word is the main thing.

So this word is basically the repair cost, not the cost repair.

The s is a linking s used in many Norwegian compounds.

You can think of it as a connector between the two noun parts:

• reparasjon
• kostnad

becomes

• reparasjonskostnad

This s does not usually have a separate meaning by itself. It is just part of how many compounds are formed naturally in Norwegian.

Not every compound uses it, so it is something you partly learn by exposure.

Yes. A phrase like kostnaden for reparasjon is possible and means roughly the same thing.

But Norwegian often prefers the compound form when it sounds natural:

• reparasjonskostnaden

The compound version is compact and very typical of Norwegian.
The for phrase can sometimes sound a little more explanatory or less technical, depending on context.

So both can work, but the one-word compound is very normal.

This sentence has the normal word order for a simple statement:

• Reparasjonskostnaden = subject
• er = verb
• høy = complement

So it is basically:

Subject + Verb + Adjective

Norwegian main clauses usually follow the verb-second rule, but in a simple statement like this, that just looks like ordinary subject-verb order.

If you move something else to the front, the verb still stays in second position:

• I år er reparasjonskostnaden høy. = This year, the repair cost is high.

A learner-friendly breakdown would be something like:

re-pa-ra-SJONS-kost-na-den

A few things to notice:

• The stress is often strongest around -sjons- and kost-
• sj in reparasjon sounds like the English sh sound
• The word is long, but Norwegian compounds are very normal, so it helps to hear it as smaller chunks:
  • reparasjon
  • kostnad
  • -en

If pronunciation feels hard, practice the parts first and then join them together.

It can do both.

In Norwegian, høy can mean physically high or tall in some contexts, but it is also commonly used for levels, amounts, and prices/costs.

So:

• et høyt fjell = a high mountain
• høye priser = high prices
• Reparasjonskostnaden er høy = the repair cost is high

This use is very natural and common.

Because the noun is definite — reparasjonskostnaden — it usually refers to a specific repair cost that is known from the context.

For example, people may already be talking about:

• a car repair
• a bill
• a planned repair job

If you wanted a more general or indefinite meaning, you would use:

• En reparasjonskostnad er høy = A repair cost is high

But that sounds less natural unless you mean one particular example.
The definite form is much more likely in real-life use when discussing a known repair.