Retorno el producte avui.

Retorno is the first-person singular present indicative of retornar.

So it means I return or, depending on context, I’m returning.

The ending -o tells you the subject is I.

Catalan often drops subject pronouns when the verb already makes the subject clear.

So:

• Retorno el producte avui = I return / I’m returning the product today
• Jo retorno el producte avui = also correct, but jo adds emphasis, like I’m the one returning it

This is different from English, where you normally must say I.

El is the masculine singular definite article, meaning the.

So:

• el producte = the product
• un producte = a product

In this sentence, the speaker is talking about a specific product, so el is used.

It can mean either one, depending on context.

In Catalan, the simple present often covers meanings that English expresses with both:

• I return the product today
• I’m returning the product today

Because avui gives a clear time reference, the sentence very naturally sounds like a planned action happening today.

Putting avui at the end is a very natural word order in Catalan.

The basic structure here is:

• Retorno = verb
• el producte = object
• avui = time expression

So the sentence follows a common pattern: Verb + object + time.

But Catalan word order is fairly flexible, so these are also possible:

• Avui retorno el producte
• Retorno avui el producte

They can sound slightly different in emphasis, but all are grammatical.

Yes.

Avui retorno el producte is perfectly correct. Putting avui first gives it more emphasis, a bit like Today I’m returning the product.

So:

• Retorno el producte avui = neutral
• Avui retorno el producte = more emphasis on today

No. Avui is used without a preposition.

So you say:

• avui = today
• demà = tomorrow
• ahir = yesterday

Not en avui or anything similar.

Yes, retornar is correct and natural, especially in a slightly careful or formal tone.

You may also hear tornar used in everyday Catalan for returning/giving something back.

Very roughly:

• retornar = to return
• tornar = to return / to go back / to give back, depending on context

So Retorno el producte avui is good Catalan, and a learner can safely use it.

Yes. You could say:

• Retornaré el producte avui

That means I will return the product today.

However, Catalan often uses the present tense for planned or near-future actions, especially when a time word like avui is already there. So Retorno el producte avui sounds very natural.

A simple learner-friendly pronunciation guide is:

• retorno ≈ reh-TOR-no
• producte ≈ proh-DUK-te
• avui ≈ ah-VWEE

The stressed syllables are:

• re-TOR-no
• pro-DUC-te
• a-VUI

Depending on the dialect, some unstressed vowels may sound weaker, but the stress pattern above is the important part for learners.

Catalan does have progressive forms, but it uses them less often than English.

English commonly says:

• I’m returning the product today

Catalan will often just use the simple present:

• Retorno el producte avui

A progressive form such as Estic retornant el producte is possible, but here it is usually unnecessary, because avui already gives the timing clearly.

Yes, but the meaning changes.

• Retorno el producte avui = I’m returning the product today
  A specific product is already known.

• Retorno un producte avui = I’m returning a product today
  The product is not being identified as a specific known one.

So el and un are not interchangeable; they change how specific the noun is.