La meva mare diu que li agrada més nedar a la piscina que al mar.

In Catalan, possessives are very often used together with the definite article. So la meva mare is the normal way to say my mother.

This is different from English, where we do not say the my mother. In Catalan, the article is usually kept:

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

There are some exceptions, especially in direct address or with certain family terms in some contexts, but for a learner, article + possessive + noun is the safest pattern.

Li is an indirect object pronoun meaning to him, to her, or to you (formal singular), depending on context.

In this sentence, it refers to la meva mare, so it means to her.

Catalan uses agradar in a structure like to be pleasing to someone, so:

• li agrada literally = it is pleasing to her
• natural English = she likes it

That is why Catalan uses li, even though English just says she likes.

Because agradar works differently from English to like.

In English:

• She likes swimming

In Catalan, the idea is more like:

• Swimming is pleasing to her

So the person who experiences the liking is expressed as an indirect object:

• m’agrada = I like
• t’agrada = you like
• li agrada = he/she likes
• ens agrada = we like

Using ella would only be for emphasis, and even then you would normally still keep the pronoun:

• A ella li agrada... = She, for her part, likes...

So ella agrada by itself would not mean she likes.

Because the thing being liked is treated as a single action: nedar = to swim / swimming.

An infinitive like nedar functions as a singular idea, so Catalan uses singular agrada:

• Li agrada nedar = She likes swimming

Compare:

• Li agrada el cafè = She likes coffee
• Li agraden els cafès forts = She likes strong coffees

So here, since nedar is one activity, agrada is singular.

Because Catalan often uses the infinitive to express activities in a general sense, just like English uses swimming.

So:

• nedar literally = to swim
• but in this kind of sentence it corresponds to English swimming

Examples:

• M’agrada llegir = I like reading
• Li agrada córrer = He/She likes running
• Ens agrada viatjar = We like travelling

So li agrada més nedar... means she likes swimming... more.

Més means more.

Here it forms a comparison:

• li agrada més X que Y = she likes X more than Y

So the structure is:

• li agrada més nedar a la piscina que al mar

This means she prefers swimming in the pool over swimming in the sea.

You will see més ... que ... a lot in Catalan:

• És més alt que jo = He is taller than me
• M’agrada més el te que el cafè = I like tea more than coffee

Because a + el contracts to al in Catalan.

So:

• a + el mar → al mar

This is very common:

• vaig al cinema = I go to the cinema
• som al centre = we are in the centre
• al mar = to/in the sea

In the sentence:

• a la piscina = in/to the pool
• al mar = in/to the sea

There is no contraction with la, so a la stays a la.

Here a is used with places after nedar to indicate where the swimming happens.

So:

• nedar a la piscina = to swim in the pool
• nedar al mar = to swim in the sea

English usually says in the pool and in the sea, but Catalan commonly uses a in this kind of context.

So do not translate the preposition too mechanically. In Catalan, a often covers meanings that English splits into to, at, and sometimes in.

Yes. It is an example of ellipsis, where something is omitted because it is understood from the first part.

The full idea would be:

• li agrada més nedar a la piscina que nedar al mar

But repeating nedar would sound unnecessary, so Catalan leaves it out:

• li agrada més nedar a la piscina que al mar

English does the same:

• She likes swimming in the pool more than in the sea

We do not need to repeat swimming after than.

Here que means that and introduces a subordinate clause.

• La meva mare diu que... = My mother says that...

So the sentence has two parts:

1. La meva mare diu = My mother says
2. que li agrada més nedar a la piscina que al mar = that she likes swimming in the pool more than in the sea

Catalan uses que very often in this way, just as English uses that.

Yes. That is also very common.

• La meva mare diu que li agrada...
• La meva mare diu que a ella li agrada... for emphasis
• A la meva mare li agrada... = My mother likes...

With agradar, Catalan often uses both:

• the noun phrase: a la meva mare
• and the pronoun: li

This is called clitic doubling and is very normal in Catalan.

So if the sentence were rearranged, you could absolutely have:

• A la meva mare li agrada més nedar a la piscina que al mar

Because that is simply how preference is usually expressed in Catalan. The most common pattern is built around agradar.

It helps to think of it this way:

• English: I like chocolate
• Catalan: Chocolate pleases me

So:

• M’agrada la xocolata = I like chocolate
• Li agrada nedar = She likes swimming

This structure is shared with Spanish and some other Romance patterns, so it is one of the first things English speakers need to get used to in Catalan.

Yes, exactly. The comparison is about the activity nedar.

The sentence is not saying she generally prefers pools to the sea in every situation. It says that, when it comes to swimming, she likes doing it more in the pool than in the sea.

That meaning comes from the structure:

• li agrada més nedar a la piscina que al mar

The comparison is tied to nedar.