Learn Hardcore Catalan: A la meva germana li fan mal les dents, i demà anirà al dentista. - My sister’s teeth hurt, and tomorrow she will go to the dentist.

Breakdown of A la meva germana li fan mal les dents, i demà anirà al dentista.

Why does the sentence use both a la meva germana and li? Don’t they both mean to my sister?

Yes, they refer to the same person, but this is normal in Catalan.

This is called clitic doubling:

In Catalan, when the indirect object is stated explicitly, especially at the beginning of the sentence, the pronoun is usually still kept:

This sounds natural. By contrast, leaving out li here would sound awkward or wrong to many speakers.

You can also say just:

Why is les dents the grammatical subject? In English, my sister feels like the subject.

In Catalan, with fer mal, the thing that hurts is treated as the subject.

So in:

the subject is les dents (the teeth), and that is why the verb is plural:

Literally, the structure is closer to:

This is very common in Catalan:

What does mean exactly?