La veïna diu que hi ha soroll a l'edifici cada nit.

La is the feminine singular definite article, meaning the.

• veí = male neighbor
• veïna = female neighbor

So la veïna means the female neighbor. Catalan usually uses the definite article in the same kinds of places English uses the.

The diaeresis over ï shows that the i is pronounced in a separate syllable, not merged with the vowel before it.

So veïna is pronounced roughly as:

• ve-ï-na

not as one smooth diphthong.

This is useful in Catalan because it tells you how to separate the syllables.

Diu is the 3rd person singular present of the verb dir, which means to say.

So:

• jo dic = I say
• tu dius = you say
• ell/ella diu = he/she says

Since the subject is la veïna = the neighbor, Catalan uses diu.

Here que means that and introduces a subordinate clause:

• La veïna diu = The neighbor says
• que hi ha soroll... = that there is noise...

In Catalan, que is very commonly used after verbs like dir, pensar, creure, etc. English sometimes drops that, but Catalan normally keeps que.

Usually no.

In English, you can say:

• The neighbor says there is noise...
• The neighbor says that there is noise...

Both are fine.

In Catalan, after diu, you normally need que before a full clause:

• La veïna diu que hi ha soroll...

Leaving it out would sound wrong in standard Catalan.

Hi ha is the standard Catalan way to say there is or there are.

So:

• hi ha soroll = there is noise
• hi ha cotxes = there are cars

It comes from the verb haver used in an existential expression. In this structure, hi is part of the fixed expression and doesn’t need to be translated word-for-word.

Because Catalan, like English, distinguishes between:

• there is / there are → existence
• is / are → identity or description

Here the idea is that noise exists in the building, so Catalan uses hi ha:

• Hi ha soroll a l'edifici = There is noise in the building

If you used és, it would not express the same idea.

Soroll means noise, and here it is being used as an uncountable noun in a general sense.

So Catalan naturally says:

• hi ha soroll = there is noise

not necessarily:

• hi ha el soroll

Using the article would change the meaning and make it sound more specific, like the noise.

This means in the building or at the building, depending on context.

Here is how it works:

• a = at / in / to
• el edifici would become l'edifici because the article el is elided before a vowel
• so a + l'edifici = a l'edifici

Catalan often uses a where English would use in.

Because before a vowel sound, el becomes l'.

Compare:

• al carrer = in/at the street
• a l'edifici = in/at the building

So with edifici, you cannot keep the full el. The article contracts by elision:

• el edifici → l'edifici

Cada nit means every night or each night.

• cada = each / every
• nit = night

After cada, Catalan normally uses the noun without an article:

• cada dia = every day
• cada setmana = every week
• cada nit = every night

So cada nit is the normal pattern.

The structure is:

• La veïna = subject
• diu = main verb
• que hi ha soroll a l'edifici cada nit = subordinate clause

So literally the order is:

• The neighbor says that there is noise in the building every night

This is a very normal Catalan sentence order: subject + verb + que-clause.

You would change veïna to veí and the article la to el:

• El veí diu que hi ha soroll a l'edifici cada nit.

Everything else stays the same.

The h in Catalan is silent, so ha is not pronounced with an English h sound.

In normal speech, hi ha is often pronounced smoothly, roughly like:

• i a
• or with a glide, something like ya

The exact sound can vary by accent and speed, but the important point is:

• the h is silent
• hi ha functions as one common expression

Yes. Catalan allows some flexibility with time expressions.

For example:

• La veïna diu que hi ha soroll a l'edifici cada nit.
• La veïna diu que cada nit hi ha soroll a l'edifici.

Both are natural. The second version emphasizes the frequency a bit more earlier in the clause.