Suppen smager lækkert.

Danish often puts definiteness on the noun itself instead of using a separate word.

• suppe = soup
• en suppe = a soup
• suppen = the soup

So the ending -en is doing the job that English the does.

Smager is the present tense of at smage = to taste.

So:

• at smage = to taste
• smager = tastes

In this sentence, it means tastes.

Because smager talks specifically about taste.

• Suppen smager lækkert = the soup tastes delicious
• Suppen er lækker = the soup is delicious / lovely

Both are natural, but smager focuses on the experience of tasting it.

After verbs like smage, Danish usually uses the -t form: godt, dårligt, lækkert, and so on.

So:

• Suppen er lækker = adjective describing the soup
• Suppen smager lækkert = -t form used after smager

A good learner rule is: after taste/smell/sound/look-type verbs, the -t form is very common.

It comes from the adjective lækker, but here it functions more like an adverbial form.

In other words, it is not really agreeing with suppen. Instead, it describes how the soup tastes.

That is why lækkert is correct here.

Yes, absolutely.

The difference is mainly one of focus:

• Suppen er lækker = the soup is delicious
• Suppen smager lækkert = the soup tastes delicious

The second version is more specifically about flavor.

The sentence is:

Suppen + smager + lækkert

That is:

• subject
• verb
• complement

This is normal Danish main-clause word order. The finite verb usually comes in second position.

You put ikke after the finite verb:

Suppen smager ikke lækkert.

So the pattern is:

subject + verb + ikke + rest of the sentence.