Quan netegem el pis, la meva filla té al·lèrgia a la pols.

Quan means when.

In this sentence it introduces a time clause: Quan netegem el pis... = When we clean the flat/apartment...

It is not being used as a question word here. So this is not When do we clean the flat? but rather When/Whenever we clean the flat, ...

Catalan often leaves out subject pronouns because the verb ending already shows the subject.

• netegem = we clean
• the ending -em tells you it is we

So Quan netegem el pis already means When we clean the flat without needing nosaltres.

You could say Quan nosaltres netegem el pis, but that would add emphasis and is not necessary in a neutral sentence.

This is a spelling pattern in Catalan.

The infinitive is netejar. In some forms, verbs ending in -jar use g before e or i:

• netejar → netegem
• pujar → pugem
• viatjar → viatgem

So netegem is the correct standard form.

Catalan often uses the present tense for habitual or repeated situations.

So Quan netegem el pis means something like:

• When we clean the flat
• Whenever we clean the flat

It describes a regular situation, not necessarily something happening right this second.

If you wanted to stress an action in progress right now, Catalan could use estar + gerund, for example estem netejant = we are cleaning.

Here el pis means the flat or the apartment.

A useful warning for learners: pis can also mean floor or storey in other contexts, but in everyday Catalan it very often means flat/apartment.

So in this sentence it means the home, not the surface under your feet.

In standard Catalan, possessives usually come with the definite article:

• la meva filla = my daughter
• el meu pare = my father
• la nostra casa = our house

That is why la meva filla is the normal form here.

English does not use an article in this structure, but Catalan usually does.

The sentence begins with a time clause: Quan netegem el pis.

A comma is commonly used after this kind of introductory clause to separate it from the main clause:

• Quan netegem el pis, la meva filla...

This helps the sentence read clearly.

Both are possible in Catalan.

• té al·lèrgia a la pols = literally she has an allergy to dust
• és al·lèrgica a la pols = she is allergic to dust

The version in your sentence is completely natural. It focuses on having an allergy as a condition.

So this is not a strange structure; it is just a different way from English of expressing the same idea.

There are two things happening here:

1. al·lèrgia normally goes with a

   • al·lèrgia a la pols
   • al·lèrgia al pol·len
   • al·lèrgia als gats

2. Catalan often uses the definite article with general nouns

   • la pols = dust

So although English says allergic to dust, Catalan says al·lèrgia a la pols, literally something like allergy to the dust.

That sounds more specific in English than it does in Catalan. In Catalan, it is the normal generic way to say it.

That dot is called the punt volat.

It shows that the two l letters are pronounced separately: l·l.

This is different from ll, which is a different Catalan sound.

So:

• al·lèrgia has l·l
• it is not spelled with ll

This is a normal spelling feature in Catalan words such as al·lèrgia, col·legi, and il·legal.