Lubię mieszać ryż z warzywami.

Lubię is the 1st person singular present tense form of lubić.

• lubić = to like
• lubię = I like

In this sentence, the main verb is I like, so Polish uses the conjugated form lubię.

A very common pattern is:

• lubię + infinitive
• I like + to do something

So:

• Lubię mieszać = I like to mix

Because after lubię, Polish normally uses the infinitive of the second verb.

So the structure is:

• lubię mieszać = I like to mix
• lubię gotować = I like to cook
• lubię czytać = I like to read

This is very similar to English I like to....

Polish often drops subject pronouns when they are already clear from the verb ending.

• lubię already means I like
• so ja is not necessary

You could say:

• Ja lubię mieszać ryż z warzywami

but that usually adds emphasis, like:

• I like mixing rice with vegetables

In neutral everyday Polish, Lubię mieszać... sounds more natural.

Because ryż is the direct object of mieszać, and here it is in the accusative case.

The important thing is that ryż is a masculine inanimate noun, and for many masculine inanimate nouns, the accusative singular looks the same as the nominative singular.

So:

• nominative: ryż
• accusative: ryż

That is why there is no visible ending change here.

Because the preposition z meaning with requires the instrumental case.

The noun here is warzywa = vegetables.
Its base singular form is warzywo = a vegetable.

In this sentence we need instrumental plural, so:

• singular: warzywo
• plural: warzywa
• instrumental plural: warzywami

So:

• z warzywami = with vegetables

This is one of the most important things to remember:
z meaning with + instrumental.

The dictionary form is warzywo.

Here is the pattern:

• warzywo = a vegetable
• warzywa = vegetables
• warzywami = with vegetables

So warzywami is not a completely different word; it is just a case form of warzywo in the plural.

Yes, z can mean different things depending on context and case.

Most commonly:

• z + instrumental = with
• z + genitive = from / off

In your sentence:

• z warzywami
• warzywami is instrumental
• so z means with

Examples:

• kawa z mlekiem = coffee with milk
• idę z kolegą = I’m going with a friend
• wracam z domu = I’m returning from home

Same preposition, different case, different meaning.

This is about aspect, which is very important in Polish.

• mieszać = imperfective
• wymieszać = perfective

In a sentence with lubię talking about something you like doing in general, Polish usually uses the imperfective verb:

• Lubię mieszać... = I like mixing / I like to mix

If you said Lubię wymieszać..., it would sound less natural in this general sense, because wymieszać focuses on completing the action.

So here mieszać is the natural choice.

It normally means a general preference or habit:

• I like to mix rice with vegetables
• I enjoy mixing rice with vegetables

It does not usually mean you are doing it right now.

If you wanted right now, you would more likely say something like:

• Mieszam teraz ryż z warzywami = I’m mixing rice with vegetables now

So lubię + infinitive usually expresses what you like doing in general.

Yes. Polish word order is fairly flexible because case endings show grammatical relationships.

The neutral order here is:

• Lubię mieszać ryż z warzywami.

But other orders are possible for emphasis, for example:

• Ryż z warzywami lubię mieszać.
• Z warzywami lubię mieszać ryż.

These are not all equally neutral, though.
For a learner, the safest and most natural version is the original one.

A rough guide for an English speaker:

• Lubię ≈ loo-byeh
• mieszać ≈ myeh-shatch
• ryż ≈ a short rɨʂ sound; roughly rizh, but not exactly English ri
• z before w here sounds closer to z
• warzywami ≈ var-zhi-VA-mi

A few useful sound notes:

• ę at the end of lubię is often pronounced very lightly, often close to e in normal speech
• sz sounds like sh
• rz usually sounds like zh as in measure
• ż also sounds like zh
• w in Polish sounds like English v

So a rough full approximation is:

• loo-byeh myeh-shatch rïzh z var-zhi-VA-mi

Not perfect, but helpful as a starting point.

It is singular.

In Polish, ryż is usually treated like an uncountable mass noun, just like rice in English.

So:

• ryż = rice

If you want to talk about portions or types, you would use other words, for example:

• porcja ryżu = a portion of rice
• rodzaj ryżu = a type of rice

But in your sentence, plain ryż is exactly what you would expect.

Yes, it is natural and correct.

It sounds like a normal statement about personal preference:

• Lubię mieszać ryż z warzywami.

A native speaker would understand it immediately as something like:

• I like mixing rice with vegetables
• I like to combine rice with vegetables

It is a good example of:

• lubię + infinitive
• direct object in the accusative
• z + instrumental for with