Kroppsspråket er tydelig.

Because Norwegian normally writes compound nouns as one word.
So kropp + språk becomes kroppsspråk.

This is very common in Norwegian. English often uses two words where Norwegian uses one compound word.

One s is a linking sound used in the compound, and the other is the first letter of språk.

So the structure is basically:

• kropp
• linking -s-
• språk
• definite ending -et

That gives kroppsspråket.

-et is the definite singular ending for a neuter noun. It works like English the.

So:

• et kroppsspråk = a body language / body language
• kroppsspråket = the body language

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

It is a neuter noun in Bokmål.

That is why you say:

• et kroppsspråk
• kroppsspråket

If it were a common-gender noun, the forms would look different.

Because Norwegian usually marks definiteness with a suffix on the noun.

So English the body language becomes kroppsspråket, not a separate word plus noun.

A separate determiner can appear in other structures, such as:

• det tydelige kroppsspråket = the clear body language

But in your sentence, the noun itself already carries the definite meaning.

Using kroppsspråket usually means you are talking about a specific body language in the situation being discussed.

So this sentence sounds like:

• the body language we can see here
• that particular body language

If you wanted to talk about body language in general, you would more naturally use the bare noun:

• Kroppsspråk er viktig. = Body language is important.

er is the present tense of å være, which means to be.

So the structure is:

• Kroppsspråket = subject
• er = is
• tydelig = clear / obvious / distinct

This is a very basic and common Norwegian sentence pattern.

Because tydelig comes after er, so it is a predicative adjective.

In Norwegian, adjectives after er do not take the definite -e form just because the noun is definite.

Compare:

• det tydelige kroppsspråket = adjective before the noun
• kroppsspråket er tydelig = adjective after er

Also, tydelig is one of those adjectives whose singular form stays tydelig.

Yes. If the adjective is placed before the noun, it changes form:

• det tydelige kroppsspråket

Here you get:

• det because the noun phrase is definite
• tydelige because the adjective is now directly modifying the noun

But after er, you use:

• Kroppsspråket er tydelig.

So the position of the adjective matters.

Yes. This is the standard pattern:

• subject + verb + complement

So:

• Kroppsspråket = subject
• er = verb
• tydelig = complement

It is very similar to English word order in a sentence like The body language is clear.