No vull que la meva filla tasti l'amanida abans que arribi la seva amiga.

They are in the present subjunctive.

• No vull que... (I don’t want that...) triggers the subjunctive in the following clause:
  • No vull que la meva filla tasti...
• abans que... also normally takes the subjunctive when it refers to something that has not happened yet:
  • abans que arribi la seva amiga

So:

• tasta / arriba = indicative
• tasti / arribi = subjunctive

This is very common in Catalan after expressions of desire, emotion, doubt, and certain time conjunctions when the action is still future or uncertain.

Because voler que (to want that / to want someone to do something) is one of the standard triggers for the subjunctive in Catalan.

Compare:

• Vull una amanida. = I want a salad.
• Vull que mengi una amanida. = I want him/her to eat a salad.

In your sentence:

• No vull que la meva filla tasti l'amanida...

The speaker is expressing a wish or desire about another person’s action, so Catalan uses the subjunctive.

Catalan usually uses the definite article + possessive + noun pattern:

• la meva filla = my daughter
• la seva amiga = her friend

This is the normal structure in Catalan, especially with family members and many everyday nouns.

So Catalan often says:

• el meu pare = my father
• la meva mare = my mother
• la seva casa = his/her house

English leaves out the article, but Catalan usually keeps it.

Because la becomes l' before a vowel sound.

• la + amanida → l'amanida

This is elision, and it helps the phrase sound more natural.

Other examples:

• l'aigua = the water
• l'escola = the school
• l'amiga = the friend

So l'amanida is simply the salad.

Not exactly.

• tastar = to taste, to try a little of something
• menjar = to eat

So tasti l'amanida suggests taking a taste or trying the salad, not necessarily eating the whole thing.

That is why tastar is a good match for English taste in this sentence.

abans que means before when it introduces a full clause with a conjugated verb.

Here it introduces:

• arribi la seva amiga

So:

• abans que arribi la seva amiga = before her friend arrives

A useful comparison:

• abans que + verb
  when there is a subject and a conjugated verb
  
  • abans que arribi
• abans de + infinitive
  when you use an infinitive instead
  
  • abans d'arribar

So you could not replace this sentence with abans d'arribi. That would be incorrect.

In standard Catalan, abans de que is generally avoided. The preferred form is:

• abans que arribi la seva amiga

Or, if the subject is the same and you want an infinitive construction:

• abans d'arribar

So the standard choices are:

• abans que + subjunctive
• abans de + infinitive

Not usually abans de que + finite verb.

seu / seva / seus / seves can mean:

• his
• her
• its
• their
• sometimes formal your

The form agrees with the thing possessed, not with the owner.

Here:

• amiga is feminine singular
• so the possessive is seva

That does not by itself tell you whether the friend belongs to him, her, or them. Context tells you.

In this sentence, the most natural reading is her friend, probably referring to the daughter’s friend.

Yes, it can be ambiguous out of context.

Catalan seu / seva is less specific than English his/her/their. So:

• la seva amiga could mean her friend, his friend, or even their friend, depending on context.

In this sentence, most learners and native speakers will probably understand it as:

• the daughter’s friend

because that is the most natural connection. But grammatically, context is what really disambiguates it.

This is the most neutral word order:

• No vull = main verb
• que la meva filla tasti l'amanida = subordinate clause
• abans que arribi la seva amiga = time clause

Catalan word order is fairly flexible, but this version sounds natural and straightforward.

For emphasis, you might move things around, but the basic structure here is the normal one for everyday speech and writing.

Without No, it becomes:

• Vull que la meva filla tasti l'amanida abans que arribi la seva amiga.

That means:

• I want my daughter to taste the salad before her friend arrives.

The grammar of tasti and arribi does not change, because vull que still triggers the subjunctive. Only the meaning changes from negative to positive.

They are:

• vull → voler = to want
• tasti → tastar = to taste
• arribi → arribar = to arrive

So the sentence contains:

• one main verb: vull
• two subjunctive verbs in subordinate clauses: tasti, arribi

Yes:

• No vull = I don’t want
• que la meva filla tasti l'amanida = my daughter to taste the salad
• abans que arribi la seva amiga = before her friend arrives

A more grammatical breakdown is:

• No vull
  main clause
• que la meva filla tasti l'amanida
  subordinate clause after voler que
• abans que arribi la seva amiga
  time clause with abans que

This kind of chunking is very useful when reading longer Catalan sentences.