Si fa fred, tapo la tassa de te i la deixo sobre la taula.

In Catalan, many weather expressions use fer (to do / to make) in an idiomatic way:

• fa fred = it is cold
• fa calor = it is hot
• fa vent = it is windy
• fa sol = it is sunny

So fa fred literally looks like it does cold, but that is just how Catalan expresses the idea naturally. The fa here is 3rd person singular of fer.

After si meaning if, Catalan normally uses the present indicative when talking about real or possible situations:

• Si fa fred, ... = if it is cold, ...

This is similar to English If it’s cold, ..., not If it will be cold, ... in standard usage.

So the sentence uses a normal present-tense condition:

• Si fa fred, tapo... i deixo...

This can describe a habit, a general rule, or something the speaker does whenever that situation happens.

Catalan often leaves out subject pronouns because the verb ending already shows who is doing the action.

• tapo = I cover
• deixo = I leave / I put down

So jo is unnecessary unless the speaker wants emphasis or contrast:

• Jo tapo la tassa... = I cover the cup...
  (maybe contrasting with someone else)

In ordinary speech, leaving out jo is completely normal.

Tapo is the 1st person singular present of tapar, which means to cover or to put a cover/lid over something.

So:

• tapar = to cover
• tapo = I cover

In this sentence, tapo la tassa de te means the speaker is covering the cup, probably to keep the tea warm.

Sometimes, but tapar is usually the more natural choice here.

• tapar often means to cover something up, put a lid on it, or block it
• cobrir can also mean to cover, but often in a broader sense, like covering a surface

For a cup, especially if you mean putting something over it, tapar la tassa sounds very natural.

So in this sentence, tapo is the better everyday choice.

La is a direct object pronoun meaning it, referring back to la tassa de te.

So the sentence first mentions the full noun:

• la tassa de te

Then, instead of repeating it, Catalan uses the pronoun:

• la deixo = I leave it

This avoids repetition, just like English does.

In Catalan, object pronouns usually go before a conjugated verb:

• la deixo = I leave it
• el veig = I see him / it
• les compro = I buy them

This is different from English, where the pronoun usually comes after the verb: leave it.

So la deixo is normal Catalan word order.

Deixar has a range of meanings, including:

• to leave
• to put / set down
• to let / allow

In this sentence, la deixo sobre la taula means something like:

• I leave it on the table
• I set it down on the table

So yes, it can sound like leave in English, but in context it often feels closer to put down or set down.

Yes, sobre can look like over, but in Catalan it is also commonly used for on in the sense of resting on a surface.

So:

• sobre la taula = on the table

This is a very normal expression.
Catalan also has damunt de, which can also mean on top of:

• damunt de la taula = on top of the table

In many contexts, both can work, but sobre la taula is perfectly natural here.

De is used to express what kind of cup it is, or what it contains as a set expression:

• una tassa de te = a cup of tea
• una tassa de cafè = a cup of coffee

If you said una tassa amb te, that would sound more like a cup with tea in it, focusing more literally on the contents. That is possible in some contexts, but it is not the normal way to say a cup of tea.

So tassa de te is the standard phrase.

Yes, both exist, and they mean different things:

• te = tea
• té = he/she/it has

The accent distinguishes them.

So in la tassa de te, it must be te without an accent because it is the noun tea.

This is a very common point of confusion for learners.

Because si without an accent means if.

Catalan also has:

• sí = yes

So:

• si fa fred = if it is cold
• sí = yes

The accent changes the meaning, so this distinction is important.

Catalan uses definite articles much like English does here:

• la tassa = the cup
• la taula = the table

In this sentence, the speaker seems to be talking about a specific cup and a specific table relevant to the situation, so the definite article is natural.

Also, Catalan generally uses articles very regularly with nouns, often even in places where English may omit them in other contexts.

Most naturally, it sounds like a habitual or general action:

• If it’s cold, I cover the cup of tea and leave it on the table.

Because everything is in the present tense, Catalan can use this structure for repeated behavior or a usual response to a situation.

Depending on context, it could also describe what the speaker is doing in a present scenario, but without extra context, a habit is the most likely reading.

Because la appears before deixo, and at that point taula has not been mentioned yet.

The sequence is:

• tapo la tassa de te
• i la deixo sobre la taula

So the listener naturally understands la as referring back to the most relevant feminine singular object already introduced: la tassa.

Also, semantically it makes sense:

• you cover the cup
• then you leave the cup on the table

You are not leaving the table on the table.

In standard Catalan, deixo is pronounced approximately like:

• DEY-shu or DEY-shoh, depending on accent and dialect

The important part for many learners is x, which in this word is pronounced like sh.

So:

• deixo sounds roughly like DAY-shoo / DEY-shu

Exact pronunciation varies somewhat across Catalan-speaking areas, but the sh sound is the key thing to notice.