El nostre pis està desordenat avui.

In standard Catalan, possessives such as meu, teu, seu, nostre, vostre normally appear with the definite article: el meu llibre, la nostra casa, el nostre pis.

So English our apartment becomes el nostre pis, not usually just nostre pis.

That is the normal word order in Catalan:

article + possessive + noun

So:

• el nostre pis
• la meva amiga
• els seus llibres

This is different from English, where our comes without an article.

Here pis means apartment or flat.

It is a very common Catalan word for a place to live in a building. So in this sentence, el nostre pis means our apartment/flat.

Be careful not to confuse it with English piece just because it looks a bit similar.

Catalan often uses estar for a temporary state or condition, and ser for identity, definition, or more permanent characteristics.

Here, desordenat avui means the apartment is messy today, so it is treated as a temporary state. That is why està is the natural choice:

• El nostre pis està desordenat avui. = It is messy today.

If you used és desordenat, it would sound more like you are describing the apartment as inherently or generally untidy, not just for today.

Because it agrees with pis, which is a masculine singular noun.

In Catalan, adjectives usually agree with the noun in gender and number:

• el pis desordenat → masculine singular
• la casa desordenada → feminine singular
• els pisos desordenats → masculine plural
• les habitacions desordenades → feminine plural

So desordenat matches pis.

Avui means today. It is an adverb of time.

Putting it at the end is completely natural in Catalan:

• El nostre pis està desordenat avui.

But Catalan is flexible, and you could also say:

• Avui el nostre pis està desordenat.

Putting avui first can give it a little more emphasis.

Yes. That is perfectly correct.

Both are natural:

• El nostre pis està desordenat avui.
• Avui el nostre pis està desordenat.

The difference is mostly about emphasis:

• sentence-final avui sounds neutral
• sentence-initial avui highlights today

Desordenat means untidy, disorganized, or messy.

It is a good choice when things are out of order. For a room or apartment, it suggests clutter or lack of organization.

If you wanted to say dirty rather than messy, you would more likely use brut:

• El pis està brut. = The apartment is dirty.
• El pis està desordenat. = The apartment is messy / untidy.

Yes. It changes to match the noun in gender and number.

The main forms are:

• nostre → masculine singular
• nostra → feminine singular
• nostres → plural masculine or feminine

Examples:

• el nostre pis
• la nostra casa
• els nostres llibres
• les nostres claus

So in your sentence, nostre is used because pis is masculine singular.

The accent shows where the stress falls: es-TÀ.

It also helps distinguish the form clearly in writing. In Catalan, written accents are important because they show pronunciation and sometimes help differentiate words or forms.

So està is pronounced with the stress on the last syllable.