La meva neboda vol decorar la sala amb globus blaus i blancs.

Because Catalan normally uses the definite article with a possessive: la meva neboda = my niece, el meu cotxe = my car.

So unlike English, where you usually say just my niece, Catalan commonly says the my niece literally, even though that is not how you translate it into English.

For a learner, article + possessive + noun is the safest normal pattern:

• la meva neboda
• el meu amic
• els nostres llibres

They all match the noun neboda, which means niece and is feminine singular.

In Catalan, articles and possessives agree with the noun in gender and number:

• la = feminine singular article
• meva = feminine singular form of my
• neboda = feminine singular noun

Compare:

• la meva neboda = my niece
• el meu nebot = my nephew

Vol is the 3rd person singular present of the verb voler, meaning to want.

So:

• jo vull = I want
• tu vols = you want
• ell/ella vol = he/she wants
• nosaltres volem = we want
• vosaltres voleu = you all want
• ells/elles volen = they want

Here, vol matches La meva neboda, which is a third-person singular subject.

Because Catalan usually puts a conjugated verb directly before an infinitive, without an extra word equivalent to English to.

So:

• vol decorar = wants to decorate
• puc anar = I can go
• necessitem parlar = we need to speak

This is very common in Catalan.

Catalan often leaves out subject pronouns because the verb form and context usually make the subject clear.

In this sentence, the subject is already stated as La meva neboda, so adding ella would be unnecessary.

Catalan is a pro-drop language, so sentences often omit subject pronouns:

• Vol decorar la sala = She/He wants to decorate the room

The exact person is understood from context.

Sala generally means room, hall, or living room / sitting room, depending on context.

So in this sentence, la sala could be understood as:

• the room
• the living room
• the hall

The most natural translation depends on the situation.

Amb means with.

Here it introduces the thing being used to decorate the room:

• amb globus = with balloons

So decorar la sala amb globus means to decorate the room with balloons.

Because in Catalan, adjectives often come after the noun, especially descriptive adjectives like colors.

So:

• globus blaus = blue balloons
• flors vermelles = red flowers
• una casa gran = a big house

This is one of the most common word-order differences from English.

Because they agree with globus, which is masculine plural.

• globus = balloons (masculine plural)
• blaus = blue (masculine plural)
• blancs = white (masculine plural)

In Catalan, adjectives must agree with the noun they describe in gender and number.

Compare:

• globus blaus i blancs = blue and white balloons
• pilotes blaves i blanques = blue and white balls

Because the noun is plural, so the adjectives must also be plural.

The basic forms are:

• blau = blue (masculine singular)
• blanc = white (masculine singular)

Their masculine plural forms are:

• blaus
• blancs

Some useful full patterns:

• blau / blava / blaus / blaves
• blanc / blanca / blancs / blanques

So with globus:

• un globus blau
• dos globus blaus

It can be a bit ambiguous, just like in English.

Globus blaus i blancs can naturally suggest:

• blue and white balloons in general

Depending on context, that might mean:

• some balloons are blue and some are white, or
• the balloons have both colors

Usually the situation makes it clear.

Yes, but the sentence as given is the most neutral and natural order:

La meva neboda vol decorar la sala amb globus blaus i blancs.

Catalan often uses: subject + verb + object + complement

You could move parts around for emphasis, but the original version is the standard straightforward one.

Yes, very similarly.

Here:

• decorar la sala = to decorate the room

Catalan uses decorar directly with the thing being decorated:

• decorar la casa
• decorar l’aula
• decorar la taula

So the structure is very close to English.