De andre sidder allerede i stuen.

De andre means the others.

• de = the / those / they, depending on context
• andre = others / other ones

Together, de andre functions as a noun phrase meaning the other people or the rest.

In this sentence, it most naturally refers to other people in a group.

Danish often uses position verbs where English would simply use to be.

Here, sidder comes from at sidde, which means to sit. So the sentence does not just say that they are in the living room; it suggests that they are sitting there, or at least seated there.

This is very natural in Danish. Compare:

• De andre er allerede i stuen = The others are already in the living room
• De andre sidder allerede i stuen = The others are already sitting in the living room

The second version gives a more specific physical picture.

Sidder is the present tense of at sidde.

A useful pattern in Danish is:

• infinitive: at sidde
• present tense: sidder
• past tense: sad
• past participle: siddet

In the present tense, Danish verbs do not change for person:

• jeg sidder
• du sidder
• han sidder
• vi sidder
• de sidder

So sidder is used for all subjects in the present.

Allerede means already.

Its position is very normal in Danish. In a main clause, adverbs like allerede, ikke, ofte, and similar words often come after the finite verb.

So:

• De andre sidder allerede i stuen

has the common pattern:

• subject: De andre
• finite verb: sidder
• adverb: allerede
• place phrase: i stuen

That placement sounds natural and standard.

I stuen means in the living room.

• i = in
• stuen = the living room

The base noun is stue, and stuen is the definite singular form, meaning the living room.

So:

• stue = a living room
• stuen = the living room

Because Danish usually marks definiteness directly on the noun.

With many common nouns, the definite singular is formed by adding an ending:

• en stue = a living room
• stuen = the living room

So in i stuen, the noun already includes the meaning the. Danish does this much more often than English.

Yes, absolutely.

That sentence is also correct, but the nuance is slightly different:

• De andre er allerede i stuen focuses on location
• De andre sidder allerede i stuen focuses on location plus posture/state

So if you simply want to say where they are, er works. If you want a more natural, vivid description of people being seated there, sidder is very common.

Because this is a normal Danish main clause with the standard verb-second structure.

The finite verb usually comes early in the clause, and in a simple statement like this the order is:

• De andre = subject
• sidder = finite verb
• allerede = adverb
• i stuen = place expression

So the structure is very straightforward and natural.

If another element is moved to the front, the verb still stays in second position. For example:

• I stuen sidder de andre allerede

That is also possible, but the original sentence is the most neutral version.

Not always, but very often.

In many everyday sentences, de andre means the other people or the others in a group. That is probably the intended meaning here.

But grammatically, it can refer to other things too if the context makes that clear. For example, it could mean the other ones in a broader sense. Still, with a sentence like this, most learners should understand it as referring to people.

Yes: the main tricky point is sidder.

A very literal translation would sound like:

• The others are already sitting in the living room

That is fine in English. But in real usage, English may sometimes prefer:

• The others are already in the living room

Danish uses verbs like sidde, stå, and ligge more often than English uses sit, stand, and lie in similar situations. So even if the exact meaning is clear, the most natural English translation may depend on context.