Innsjøen er dyp.

In Norwegian, the definite article is often attached to the end of the noun instead of being a separate word.

• innsjø = lake
• innsjøen = the lake

So -en here works like English the.

This means:

• en innsjø = a lake
• innsjøen = the lake

Because Norwegian usually marks definiteness directly on the noun.

In English, you say:

• the lake

In Norwegian, you often say:

• innsjøen

That final -en already means the.

A separate word such as den is usually used when there is an adjective before the noun:

• den dype innsjøen = the deep lake

But in Innsjøen er dyp, there is no adjective inside the noun phrase, so innsjøen by itself is enough.

Er means is / are / am, depending on context. It is the present tense of å være (to be).

Examples:

• Jeg er = I am
• Du er = You are
• Innsjøen er dyp = The lake is deep

Unlike English, Norwegian does not change the verb form for different persons in the present tense. It stays er.

Because Norwegian adjectives agree with the noun in gender and number.

Here, innsjøen is singular and is treated here as an en-noun, so the adjective in predicate position is:

• dyp = deep

Compare:

• Innsjøen er dyp. = The lake is deep.
• Havet er dypt. = The sea is deep.
  (hav is neuter, so dypt)
• Innsjøene er dype. = The lakes are deep.
  (plural, so dype)

So dyp is the correct form for this sentence.

Because dyp here is a predicate adjective: it comes after er and describes the subject.

In Norwegian, predicate adjectives usually agree with gender and number, but not with definiteness in the same way adjectives before nouns do.

So:

• innsjøen er dyp = correct
• not innsjøen er dype

Compare this with an adjective before the noun:

• den dype innsjøen = the deep lake

There, the adjective is inside the noun phrase, so it takes the -e form.

No. This is the normal word order for a simple Norwegian statement:

• Subject + verb + adjective
• Innsjøen er dyp

That matches English fairly closely:

• The lake is deep

So this sentence is very straightforward in structure.

Usually yes in translation, but literally innsjø means an inland lake.

So:

• innsjø = lake
• literally: inland lake

This helps distinguish it from sjø, which can mean sea, and in some contexts or dialects may also refer to a lake.

For most learners, translating innsjø as lake is perfectly fine.

You would say:

• en dyp innsjø = a deep lake
• den dype innsjøen = the deep lake

This shows an important pattern:

• with an indefinite noun: en dyp innsjø
• with a definite noun + adjective: den dype innsjøen

That second pattern is often called double definiteness, because Norwegian uses both:

1. a separate definite word: den
2. a definite ending on the noun: -en

A rough guide is:

• Innsjøen ≈ INN-shø-en
• er ≈ air (depending on accent)
• dyp ≈ deep, but with rounded lips on the vowel

A few pronunciation notes:

• sj in innsjøen sounds like English sh
• ø does not exist in standard English; it is similar to the vowel in French bleu or German schön
• y in dyp is also not a normal English vowel; say something like ee but with your lips rounded

So the sentence may be difficult to pronounce exactly for an English speaker, even if the grammar is simple.

Yes. This one sentence teaches several very common Norwegian patterns:

• Definite noun ending: innsjøen = the lake
• Present tense of to be: er
• Predicate adjective: dyp
• Basic statement word order: subject + verb + complement

So even though the sentence is short, it is a very useful model for making many similar sentences, such as:

• Boken er tung. = The book is heavy.
• Veien er lang. = The road is long.
• Døren er åpen. = The door is open.