La meva mare vol canviar l'hora del dinar.

This is normal in Catalan. With many family members and possessives, Catalan often uses the definite article:

• la meva mare = my mother
• el meu pare = my father
• la teva germana = your sister

So although it looks like the my mother word-for-word, that is not how it functions. In natural English, you just translate it as my mother.

Catalan can sometimes omit the article in certain styles or varieties, but la meva mare is a very standard form.

Because the possessive adjective has to agree with the noun it describes.

mare is a feminine singular noun, so you use the feminine singular form:

• meu = masculine singular
• meva = feminine singular
• meus = masculine plural
• meves = feminine plural

So:

• el meu pare
• la meva mare

Vol is the third person singular of the verb voler, which means to want.

Here are some present-tense forms of voler:

• 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

So La meva mare vol... means My mother wants...

Because Catalan works like English here: after to want, you usually use another verb in the infinitive.

• vol canviar = wants to change
• literally: wants change

More examples:

• Vull menjar. = I want to eat.
• Vol anar-hi. = He/She wants to go there.

So vol canviar is the normal structure.

Canviar usually means to change.

In this sentence, canviar l'hora del dinar means to change the time of lunch or to change lunchtime.

Depending on context, canviar can also mean things like:

• to switch
• to exchange
• to replace

But here to change is the most natural meaning.

Because hora starts with a vowel sound, and Catalan usually contracts la to l' before a vowel:

• la amiga → l'amiga
• la escola → l'escola
• la hora → l'hora

So l'hora simply means the hour/time.

In this sentence, hora is best understood as time in the sense of scheduled time.

So:

• l'hora del dinar = the time of lunch / lunchtime

It does not necessarily mean a literal sixty-minute hour here. It refers more to when lunch happens.

Del is a contraction of de + el:

• de = of
• el = the
• del = of the

So:

• l'hora del dinar
• literally = the time of the lunch
• naturally = the time of lunch / lunchtime

This contraction is very common in Catalan.

Dinar usually means lunch or the midday meal.

It can be:

• a noun: el dinar = lunch
• a verb: dinar = to have lunch / to eat lunch

In your sentence, it is a noun, because it appears as el dinar inside del dinar.

Yes, and the meaning is very similar, but there can be a slight nuance.

• l'hora del dinar = the time of lunch / the lunchtime
• l'hora de dinar = the time to eat lunch

In many contexts, both are natural.
Del dinar points a bit more to the lunch period/meal, while de dinar can feel a bit more like the act of having lunch.

In everyday speech, both may be understood perfectly well.

Catalan word order here is very similar to English:

• La meva mare = subject
• vol = verb
• canviar = infinitive complement
• l'hora del dinar = object

So the structure is:

subject + conjugated verb + infinitive + object

That is why it maps neatly onto English:

My mother wants to change the time of lunch.

A simple approximate pronunciation for an English speaker is:

LOR-uh del dee-NAR

A few notes:

• l'hora sounds like the l joins directly to hora
• h in Catalan is silent
• dinar is stressed on the last syllable: di-NAR

This is only an approximation, but it is enough to get started.

Mare literally means mother, but in real use it can often correspond to mom depending on context and tone.

So:

• la meva mare can mean my mother
• in many everyday contexts, it may sound as natural as my mom

If someone wants to sound more affectionate or informal, there are also other family-style forms in some varieties, but mare is the standard basic word.