Komposten är full.

Because -en is the definite singular ending for many en-words in Swedish.

• kompost = a compost / compost bin / compost heap
• komposten = the compost / the compost bin / the compost heap

So Swedish often puts the at the end of the noun instead of using a separate word like English does.

It is an en-word.

That is why the indefinite form is:

• en kompost

and the definite singular form is:

• komposten

If it were an ett-word, the definite ending would typically be -et instead.

Är is the present tense of vara, which means to be.

So:

• är = is / are / am, depending on context

In this sentence, it works just like English is:

• Komposten är full.
• The compost bin is full.

Swedish verbs do not change depending on the subject, so är stays the same with jag, du, den, vi, etc.

Because full is a predicate adjective here, and it agrees with the noun.

Since komposten is:

• singular
• common gender (en-word)

the correct form is full.

Compare:

• Komposten är full. = common gender singular
• Huset är fullt. = neuter singular
• Komposterna är fulla. = plural

So the form depends on what is being described.

Because Swedish usually marks definiteness on the noun itself.

English uses a separate article:

• the compost bin

Swedish often uses a suffix instead:

• komposten

So the idea of the is already built into komposten.

Yes, very often it does. In this sentence it means full in the ordinary sense: there is no more room.

But just like in English, full can also sometimes mean drunk, depending on context.

Here, because the subject is komposten, the meaning is clearly full, not drunk.

Är is pronounced roughly like a short vowel sound similar to the e in some pronunciations of bed, followed by an r-sound, though the exact sound depends on accent.

A simple learner-friendly approximation is:

• är ≈ air without fully saying the English diphthong

The letter ä is important here. It is not the same as a.

This is the basic Swedish main-clause order:

• subject + verb + complement

So:

• Komposten = subject
• är = verb
• full = complement

Very straightforward.

One important Swedish rule is that in main clauses, the finite verb usually comes in second position. So if you start with another element, the verb still stays second:

• Nu är komposten full. = Now the compost bin is full.

Yes. Depending on context, komposten could refer to:

• a compost bin
• a compost heap
• the compost itself

Swedish often leaves this a bit more general than English does, and the exact translation depends on the situation.

Because full is an adjective after the verb är, not a noun phrase.

In English too, we say:

• The compost bin is full

not:

• The compost bin is a full

So Swedish works similarly here. After vara (to be), adjectives like full, tom, stor, klar describe the subject directly without an article.

Then you would use the indefinite noun:

• En kompost är full.

But in real usage, that often sounds less natural unless you are talking about one compost bin among several or introducing it for the first time.

Very often, Swedish prefers the definite form when talking about a specific known thing:

• Komposten är full. = The compost bin is full.