La cuina fa bona olor quan el tomàquet es barreja amb l'oli.

Fer olor is a very common Catalan expression for giving off a smell. So fa bona olor is the natural way to say that something smells good.

Literally, it looks like makes good smell, but you should treat it as an idiomatic chunk:

• fa olor = smells
• fa bona olor = smells good
• fa mala olor = smells bad

So even though the structure is different from English, it is completely normal Catalan.

Because olor is a feminine noun in Catalan, and adjectives must agree with the noun they describe.

So:

• olor = feminine singular
• therefore bona = feminine singular form of bo

That is why you get bona olor and not bo olor.

Catalan uses definite articles more often than English does. Here la cuina is simply the normal way to say the kitchen as the subject of the sentence.

A native English speaker may expect something more like just kitchen, but Catalan usually wants the article with a noun like this. So la cuina sounds natural and complete.

For the same general reason: Catalan often uses the definite article with nouns where English might not, especially when talking about something as a category, ingredient, or substance in a general way.

So el tomàquet here does not have to mean one specific tomato in a very strict sense. It can refer naturally to tomato as an ingredient in the situation being described.

This is very common in Catalan:

• el pa
• l'oli
• el formatge
• el tomàquet

The verb is barrejar = to mix. In this sentence it appears as barrejar-se, which is a very common pronominal form.

So:

• barrejar can be transitive: Barrejo el tomàquet amb l'oli = I mix the tomato with the oil.
• barrejar-se can be more like to mix / to get mixed: El tomàquet es barreja amb l'oli.

The es does not necessarily mean the tomato is literally mixing itself on purpose. It is part of a normal Catalan verb pattern that often gives an intransitive or middle-type meaning.

Not in a strongly literal English sense. Grammatically, it is a pronominal form, and English learners often first interpret it as mixes itself, but that is not the best way to understand it here.

A better way to think about it is:

• barrejar = to mix something
• barrejar-se = to mix together / to become mixed

So in this sentence, es barreja amb l'oli is just the natural Catalan way to say that the tomato mixes with the oil.

Because Catalan drops the vowel of the article el before a word beginning with a vowel sound.

So:

• el + oli becomes l'oli

This is called elision. The same thing happens with many words:

• l'aigua
• l'home
• l'olor

So amb l'oli is just with the oil, with the article shortened before the vowel.

Quan means when and introduces a time clause.

In this sentence, it connects the two ideas:

• the kitchen smells good
• this happens when the tomato mixes with the oil

So quan el tomàquet es barreja amb l'oli is the time condition or time frame for the main clause.

Because the sentence expresses a general, normal fact: this is what happens in that situation.

Catalan often uses the present tense for:

• general truths
• habitual actions
• typical results

So the present tense here does not mean only right now. It can also mean whenever this happens, this is the result.

Yes. Catalan allows both orders here.

You can say:

• La cuina fa bona olor quan el tomàquet es barreja amb l'oli.
• Quan el tomàquet es barreja amb l'oli, la cuina fa bona olor.

Both are natural. If the quan clause comes first, a comma is normally used in writing.

The accent in tomàquet shows that the stress falls on mà.

So the stressed part is:

• to-MÀ-quet

A rough English-friendly pronunciation is toh-MAH-ket, though the exact vowels vary by dialect.

A useful spelling note:

• qu before e gives a k sound

So -quet sounds like ket, not like English kwet.

It can mean both, depending on context.

• la cuina = the kitchen
• la cuina catalana = Catalan cuisine / Catalan cooking

In this sentence, because it is the place that smells good, la cuina is understood as the kitchen, not cuisine.