Gjeldsgraden er høy.

Because -en marks the definite singular form of a common-gender noun in Norwegian.

• en gjeldsgrad = a debt ratio / an indebtedness ratio
• gjeldsgraden = the debt ratio

So the sentence is talking about a specific debt ratio, not just any debt ratio.

It is a compound noun:

• gjeld = debt
• grad = degree, level, rate
• -en = the definite ending

So:

• gjeldsgrad = debt ratio / degree of indebtedness
• gjeldsgraden = the debt ratio

The -s- in the middle is a linking sound used in many Norwegian compounds.

That -s- is a linking s. It often appears in compound nouns and does not usually have a separate meaning by itself.

So:

• gjeld
  • grad becomes gjeldsgrad

You cannot always predict perfectly when Norwegian will use a linking -s-, so this is something learners often just have to get used to word by word.

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

So:

• er = is / are

In this sentence:

• Gjeldsgraden er høy = The debt ratio is high

This is the normal way to make a simple statement with to be in Norwegian.

Because høy is the correct adjective form for a singular common-gender noun when the adjective comes after er.

Compare:

• En gjeldsgrad er høy
• Et nivå er høyt
• Tallene er høye

So the pattern is:

• common gender singular: høy
• neuter singular: høyt
• plural/definite plural: høye

Since gjeldsgrad is a common-gender noun, høy is right.

In modern Norwegian grammar, it is usually better to say it is a common-gender noun rather than a masculine noun.

You would use:

• en gjeldsgrad
• gjeldsgraden

Many learners are taught masculine, feminine, neuter, but in Bokmål, a lot of nouns behave as common gender nouns in practice. For this word, just remember the pattern en ... / ...en.

Yes, høy is the normal word here.

In Norwegian, høy is used not only for physical height, but also for things like:

• prices
• levels
• rates
• percentages
• risk
• debt

So:

• høy pris = high price
• høy rente = high interest rate
• høy gjeldsgrad = high debt ratio

Tall usually describes a person or object that has physical height:

• Han er tall = He is tall

So gjeldsgraden er tall would be wrong.

Not in normal standard usage for this kind of sentence.

Gjeldsgraden er høy sounds natural because it refers to a specific debt ratio: the debt ratio.

If you want an indefinite version, you would normally need an article:

• En gjeldsgrad er høy = A debt ratio is high

But that sentence sounds a bit unusual unless you are making a very specific contrast or definition.

For a general statement, Norwegian would often phrase it differently, for example:

• Gjeldsgraden kan være høy = The debt ratio can be high
• En høy gjeldsgrad kan være risikabel = A high debt ratio can be risky

The basic word order is:

• subject + verb + adjective

So here:

• Gjeldsgraden = subject
• er = verb
• høy = adjective/predicative complement

This is the normal structure for a simple statement in Norwegian.

A rough learner-friendly approximation is:

YELDS-grah-den er hoy

A few helpful notes:

• In gjeld, the g is not strongly pronounced; the word begins roughly with a y sound.
• graden has a clear grah- sound.
• høy contains the Norwegian øy diphthong, which does not match English perfectly. It is somewhat similar to hoy, but with a more rounded starting sound.

You do not need perfect pronunciation right away; the most important thing is recognizing the word parts and stress pattern.

This sentence is standard Bokmål.

A Nynorsk version would typically use:

• Gjeldsgraden er høg

So the main difference here is:

• Bokmål: høy
• Nynorsk: høg

Everything else in the sentence is very similar.