A l'exposició d'avui hi ha una pintura d'una artista de la ciutat.

In Catalan, a is very commonly used to mark location, especially with events or places: a l'exposició, a l'escola, al museu.

So A l'exposició d'avui means At today’s exhibition.

Even if English uses at or in, Catalan often just uses a.

Because al is the contraction of a + el.

But exposició is feminine, so its article is la:

• la exposició

Since la becomes l' before a vowel, you get:

• l'exposició

And with the preposition:

• a + l'exposició → a l'exposició

So:

• al = a + el
• a l' = a + la / el before a vowel sound, after apostrophe

d'avui literally means of today.

Catalan often expresses this idea with noun + de + time expression:

• l'exposició d'avui = today’s exhibition
• el diari d'avui = today’s newspaper
• la reunió d'ahir = yesterday’s meeting

So this is a very natural Catalan structure.

hi ha means there is or there are.

In this sentence:

• hi ha una pintura = there is a painting

It is one of the most important everyday expressions in Catalan, and it is best learned as a fixed unit:

• hi ha = there is / there are

Historically, hi is a locative element, something like there. But for learners, the easiest way to think about it is this:

You usually learn hi ha as one complete expression meaning:

• there is
• there are

So even if there is already a location phrase in the sentence (A l'exposició d'avui), Catalan still uses hi ha.

Yes.

In the present tense, hi ha is used for both singular and plural:

• Hi ha una pintura. = There is a painting.
• Hi ha dues pintures. = There are two paintings.

So the number is shown by the noun, not by changing hi ha.

Yes. artista is a common-gender noun: the form stays the same, and the article shows the gender.

So:

• un artista = a male artist
• una artista = a female artist

In your sentence, una artista tells you the artist is female.

Because de is apostrophized before a vowel:

• de + una → d'una

This is very common in Catalan:

• d'una artista
• d'un amic
• d'avui

So the apostrophe is just a regular spelling rule.

Here, de links the painting to the artist. In English, we often translate that as by:

• una pintura d'una artista = a painting by an artist

Catalan uses de in many relationships where English might use of, from, or by, depending on context.

So in this sentence, de is introducing the creator of the painting.

The most natural reading is that it modifies artista:

• una artista de la ciutat = an artist from the city

So the full noun phrase means:

• a painting by an artist from the city

Grammatically, Catalan often places this kind of descriptive phrase right after the noun it describes.

Yes, Catalan word order is somewhat flexible, but this version is very natural.

This sentence is organized like this:

• A l'exposició d'avui = setting/location first
• hi ha = there is
• una pintura d'una artista de la ciutat = the thing being introduced

Another possible order would be:

• Hi ha una pintura d'una artista de la ciutat a l'exposició d'avui.

That is also understandable, but the original sentence sounds more natural if you want to set the scene first.

The accent in exposició shows where the stress falls:

• ex-po-si-CIÓ

Without getting too technical, the written accent tells you that the last syllable is stressed.

This is helpful for pronunciation, because Catalan spelling uses accents quite systematically.

In normal speech, hi ha is pronounced roughly like:

• ee AH

The two words are short and often flow together smoothly.

A very rough guide for an English speaker:

• hi ≈ ee
• ha ≈ ah

So hi ha sounds something like ee-ah, though exact pronunciation depends on accent and speed.