Lubię makaron z warzywami, ale mój brat woli ryż z mięsem.

They are two different verbs, and they are also conjugated for different people.

• lubię = I like
  It comes from lubić.
• woli = he/she prefers
  It comes from woleć.

In this sentence:

• Lubię makaron... = I like pasta...
• mój brat woli... = my brother prefers...

So the endings change because the subject changes:

• ja lubię = I like
• on/ona woli = he/she prefers

Because brat is a masculine noun, and the possessive adjective must agree with it.

• mój = my, for masculine singular nouns
• moja = my, for feminine singular nouns
• moje = my, for neuter singular nouns

Examples:

• mój brat = my brother
• moja siostra = my sister
• moje dziecko = my child

So brat is masculine, which is why we use mój.

They are the direct objects of the sentence, so in Polish they are in the accusative case. However, for many masculine inanimate nouns, the accusative looks exactly like the nominative.

So:

• makaron
  nominative: makaron
  accusative: makaron
• ryż
  nominative: ryż
  accusative: ryż

That is why the forms do not visibly change here.

This is very common in Polish with masculine inanimate nouns.

Because the preposition z meaning with takes the instrumental case.

So the nouns after z must change:

• warzywa → z warzywami = with vegetables
• mięso → z mięsem = with meat

This is one of the most important things to remember about Polish prepositions: they often require a specific case.

Here:

• z warzywami = with vegetables
• z mięsem = with meat

That is just the natural way these foods are commonly expressed.

• warzywa is often used in the plural to mean vegetables in general.
• mięso is usually an uncountable noun, so it is commonly singular, like meat in English.

So:

• makaron z warzywami = pasta with vegetables
• ryż z mięsem = rice with meat

This is more about normal usage than grammar alone.

Ale means but.

In Polish, a comma is normally placed before coordinating conjunctions like ale when they connect two clauses.

So:

• Lubię makaron z warzywami, ale mój brat woli ryż z mięsem.

This is the normal punctuation, just like in English:

• I like pasta with vegetables, but my brother prefers rice with meat.

Yes, you could, but it would sound a bit different.

Polish often omits words like my, your, his, etc. when the meaning is already clear. So:

• ale brat woli ryż z mięsem is possible

However, mój brat sounds more natural here because it clearly sets up the contrast:

• I like... but my brother prefers...

So mój is not strictly necessary for grammar, but it helps with clarity and emphasis.

They are related, but not the same.

• lubić = to like
• woleć = to prefer

So:

• Lubię makaron = I like pasta
• Wolę ryż = I prefer rice

In this sentence, the speaker says what they like, and then contrasts that with what the brother prefers.

A simple learner-friendly pronunciation is:

• lubię ≈ LOO-byeh

The final ę is a nasal vowel, but at the end of a word in normal speech it is often pronounced less strongly than learners expect. In careful pronunciation, it is nasalized, but in everyday speech it may sound closer to e or eh with some nasal quality.

A few other useful pronunciation notes from the sentence:

• ryż ≈ rïsh
  The ż sounds like the s in measure.
• mój ≈ mooy or moo-yi
  depending on the speaker
• mięsem begins with a soft mię, roughly myen with nasalization

You do not need perfect nasal vowels at the beginning. Being understood matters more.

Yes. Polish word order is more flexible than English because case endings show grammatical relationships.

The sentence as written is neutral and natural:

• Lubię makaron z warzywami, ale mój brat woli ryż z mięsem.

But other orders are possible for emphasis, for example:

• Makaron z warzywami lubię, ale mój brat woli ryż z mięsem.

This puts extra focus on makaron z warzywami.

Even though Polish allows flexibility, learners should usually start with the basic, neutral order:

• verb + object
• subject + verb + object

That will sound natural in most situations.

Because Polish usually does not need subject pronouns when the verb ending already shows who is doing the action.

• lubię already means I like
• wolę would already mean I prefer
• woli already means he/she prefers

So ja is often omitted unless you want emphasis or contrast.

For example:

• Ja lubię makaron, ale on woli ryż.

This version is more emphatic: I like pasta, but he prefers rice.

In your sentence, leaving out ja is completely normal and natural.