El vestidor és allà.

Because vestidor is a masculine singular noun in Catalan, so it takes the masculine singular definite article el.

• el = the for masculine singular nouns
• la = the for feminine singular nouns

So:

• el vestidor = the dressing room / the changing room

A lot of Catalan nouns ending in -or are masculine, and vestidor is one of them.

Vestidor usually means a place used for getting dressed or changed.

Depending on context, it can mean:

• dressing room
• changing room
• sometimes walk-in closet / dressing room in a house

So the exact English translation depends on the situation, but the Catalan word itself is perfectly normal for a room where people dress or change clothes.

És is the 3rd person singular form of ser, so it means is.

• és = is

The accent matters because it distinguishes és from es.

• és = is
• es = a pronoun, often meaning something like oneself / himself / herself / itself, depending on the sentence

The accent on é also tells you the vowel is pronounced as a close e sound.

This is a very common question, especially if you know Spanish.

In Catalan, ser is very often used to say where something is located, especially in simple identification or location sentences like this one.

So:

• El vestidor és allà = The dressing room is there

For beginners, the safest choice in a sentence like this is és.

Very roughly:

• ser often identifies or locates
• estar often describes a state or condition, and can also be used in some location contexts

But in this sentence, és is the normal, natural choice.

Allà means there or over there.

It usually suggests some distance from the speaker, often a little more like over there in English.

Catalan also has allí, which can also mean there. In many situations, allí and allà are very close in meaning, though some speakers feel that:

• allí = there
• allà = over there / farther away

In real life, usage varies by region and by speaker.

Also, the accent in allà shows that the stress falls on the last syllable: a-LLÀ.

Not in the same way.

Use hi ha when you mean there is / there are and you are introducing something as existing somewhere:

• Hi ha un vestidor allà. = There is a dressing room there.

Use és when the thing is already specific or known, and you are saying where it is:

• El vestidor és allà. = The dressing room is there.

So the difference is:

• hi ha = existence
• és = identity/location of a specific thing

The neutral, standard word order is:

• El vestidor és allà.

That is the most natural pattern for a beginner to use.

You can move parts of the sentence around in Catalan for emphasis, but Allà és el vestidor sounds marked and is not the basic everyday version you should learn first.

So if you just want to say The dressing room is there, stick with:

• El vestidor és allà.

A rough pronunciation guide is:

• el ves-ti-DOR ez a-LYA

A few helpful points:

• vestidor is stressed on the last syllable: -dor
• és sounds like ez or es, depending on accent
• allà is stressed on the last syllable: a-llà
• the ll sound is traditionally a palatal sound, something like ly in million, although in many modern accents it is closer to y

So allà may sound roughly like:

• a-LYA
• or in some accents more like a-YA

Both are normal depending on the variety of Catalan.