Learn Hardcore German: Im Wohnzimmer liegen schon bunte Luftballons, und auf dem Tisch liegt eine neue Tischdecke. - There are already colorful balloons in the living room, and on the table there is a new tablecloth.

Im Wohnzimmer liegen schon bunte Luftballons – the balloons are lying around, usually on the floor, sofa, etc.
... und auf dem Tisch liegt eine neue Tischdecke – the tablecloth is lying flat on the table.

You could say Im Wohnzimmer sind schon bunte Luftballons, and people would understand you, but liegen paints a more vivid picture of how the objects are positioned. Using these specific verbs sounds more natural and idiomatic in German.

Why is it liegen with Luftballons but liegt with Tischdecke?

That’s subject–verb agreement:

bunte Luftballons is plural → verb must be plural → liegen
- Im Wohnzimmer liegen schon bunte Luftballons.
eine neue Tischdecke is singular → verb must be singular → liegt
- auf dem Tisch liegt eine neue Tischdecke.

So the verb form always matches the grammatical number (singular/plural) of the subject, just like there is / there are in English, but more strictly.

What is im in Im Wohnzimmer? Why not in dem Wohnzimmer?

im is simply a contraction:

im = in dem

So:

Im Wohnzimmer = In dem Wohnzimmer = in the living room.

This uses the dative case (dem) because:

in is a two‑way preposition (can take accusative or dative),
here it expresses location (where something is), not movement.

With location, in takes the dative:

in dem Wohnzimmer → im Wohnzimmer (location)
contrast: in das Wohnzimmer → ins Wohnzimmer = into the living room (movement, accusative)

Why is it auf dem Tisch and not auf den Tisch?

Again, this is about case with a two‑way preposition:

auf can take accusative (movement) or dative (location).

Here the meaning is where the tablecloth is (location), not where it is being put:

auf dem Tisch (dative) = on the table (resting there)
auf den Tisch (accusative) = onto the table (movement to that place)

So:

auf dem Tisch liegt eine neue Tischdecke – there is a tablecloth lying on the table.
Er legt die Tischdecke auf den Tisch – He puts the tablecloth onto the table.

Why does the verb come before the subject in liegen schon bunte Luftballons and liegt eine neue Tischdecke?

This is the verb‑second (V2) rule in German main clauses.

German main clauses must have the conjugated verb in the 2nd position, but the first position can be almost anything: subject, time, place, etc.

First clause:
- Im Wohnzimmer (place phrase in position 1)
- liegen (verb in position 2)
- schon bunte Luftballons (rest of the sentence, including the subject)
Second clause:
- auf dem Tisch (place phrase in position 1)
- liegt (verb in position 2)
- eine neue Tischdecke (subject + adjective)

If you start with the subject instead, you still keep the verb in second position:

Bunte Luftballons liegen schon im Wohnzimmer.
Eine neue Tischdecke liegt auf dem Tisch.

Both word orders are correct; the difference is what you want to emphasize or put in first position (here: the locations).

What does schon add here, and where should it go in the sentence?

In this sentence schon means already:

Im Wohnzimmer liegen schon bunte Luftballons = There are already colorful balloons lying in the living room.

It suggests that preparations are underway or that this happened earlier than expected.

Word order: schon is a mid‑position adverb, and the usual, natural place is:

after the verb and before the main part of the predicate/objects:
- liegen schon bunte Luftballons
- sie ist schon da
- wir haben schon gegessen

Other positions are possible but may sound marked or odd in everyday speech, for example:

Schon liegen im Wohnzimmer bunte Luftballons – very emphatic, stylistically marked.
Im Wohnzimmer liegen bunte Luftballons schon – possible but sounds unusual; most speakers would not say it this way in normal conversation.

So the given position (liegen schon ...) is the most natural.

Why is it bunte Luftballons and eine neue Tischdecke? How do the adjective endings work?

There are two different adjective declension patterns here.

bunte Luftballons

Luftballons is plural, no article, nominative.
With no article in the plural, adjectives take strong endings:
- nominative plural (all genders): bunte
So we get: bunte Luftballons = colorful balloons.

eine neue Tischdecke

Tischdecke is feminine, singular.
eine is an indefinite article, marking gender, number, case.
After ein‑words (ein, eine, kein, mein, dein, etc.), adjectives take mixed endings.
Nominative feminine singular:
- article: eine
- adjective: neue
So: eine neue Tischdecke = a new tablecloth.

Summary:

No article, nom. plural → bunte Luftballons
Indefinite article, nom. fem. sg. → eine neue Tischdecke

Why is Luftballons spelled with -s in the plural, not Luftballone?

Luftballon is a loanword (from French ballon), and many such words can take -s in the plural:

der Luftballon → die Luftballons
der Ballon → die Ballons

You will also see Luftballone used; dictionaries usually list Luftballons and Luftballone as parallel plurals. In everyday modern German, Luftballons with -s is very common and sounds entirely natural.

So in this sentence bunte Luftballons is perfectly standard.

Why is there a comma before und?

You have:

Im Wohnzimmer liegen schon bunte Luftballons, und auf dem Tisch liegt eine neue Tischdecke.

Both parts are independent main clauses:

Im Wohnzimmer liegen schon bunte Luftballons.
Auf dem Tisch liegt eine neue Tischdecke.

In modern German spelling, when und connects two main clauses, the comma is optional:

… Luftballons, und auf dem Tisch liegt … ✅
… Luftballons und auf dem Tisch liegt … ✅

Using the comma can make the structure clearer and is often preferred in more careful or written style, but leaving it out is not wrong.

Why is Wohnzimmer neuter, and what does the compound mean literally?

Wohnzimmer is a compound:

wohnen / Wohn‑ – to live, living
das Zimmer – the room

So das Wohnzimmer = literally the living room.

The gender of German compounds is determined by the last part of the compound:

das Zimmer → therefore das Wohnzimmer (neuter)

In the sentence, we see the dative form dem Wohnzimmer (inside im = in dem), because of the preposition in with location.

Why is Tischdecke one word and capitalized?

German very often forms compound nouns by joining smaller nouns:

der Tisch – table
die Decke – cover, blanket

Together: die Tischdecke – literally table cover → tablecloth.

In German:

Nouns are always capitalized.
Noun+noun compounds are usually written as one word, not separated.

So Tischdecke must be written as a single, capitalized word.