Ja wolę majonez niż musztardę.

Yes. In Polish, subject pronouns like ja (I) are often omitted because the verb ending already shows who the subject is.

• wolę = I prefer

So:

• Wolę majonez niż musztardę = perfectly natural
• Ja wolę majonez niż musztardę = also correct, but ja adds emphasis

Using ja can suggest contrast, for example:

• Ja wolę majonez, a on woli musztardę.
  I prefer mayonnaise, and he prefers mustard.

Wolę is the 1st person singular form of the verb woleć (to prefer).

Present tense of woleć:

• ja wolę = I prefer
• ty wolisz = you prefer
• on/ona/ono woli = he/she/it prefers
• my wolimy = we prefer
• wy wolicie = you (plural) prefer
• oni/one wolą = they prefer

So in this sentence, wolę by itself already tells you the subject is I.

They actually are both functioning as objects, but Polish case endings depend on the noun’s gender and type.

After woleć, the thing preferred is usually in the accusative case.

• majonez is a masculine inanimate noun
  Its accusative singular is the same as its nominative singular: majonez
• musztarda is a feminine noun
  Its accusative singular changes to musztardę

So:

• nominative: majonez, musztarda
• accusative: majonez, musztardę

That is why the two words look different.

In this sentence, niż means than in a comparison: prefer X than Y / prefer X to Y.

Here the second noun also appears in the accusative:

• wolę majonez niż musztardę

This is a common pattern with woleć ... niż ...

So a learner can think of the whole structure as:

• woleć + accusative + niż + accusative

Examples:

• Wolę kawę niż herbatę.
• Wolę kino niż teatr.

Usually, with woleć, Polish most naturally uses niż:

• Wolę majonez niż musztardę.

Using od here would sound unnatural in standard Polish for this structure.

In general:

• niż is the normal word for than in many comparisons
• od is often used with comparative adjectives/adverbs, for example:
  • lepszy od... = better than...
  • wyższy od... = taller than...

So for prefer, stick with:

• woleć ... niż ...

They are not the same.

• lubię = I like
• wolę = I prefer

So:

• Lubię majonez. = I like mayonnaise.
• Wolę majonez niż musztardę. = I prefer mayonnaise to mustard.

You can like both things and still prefer one:

• Lubię majonez i musztardę, ale wolę majonez.
  I like mayonnaise and mustard, but I prefer mayonnaise.

Not completely. Polish word order is more flexible than English, but some orders sound more neutral than others.

The most neutral version is:

• (Ja) wolę majonez niż musztardę.

You may also hear variations for emphasis, such as:

• Majonez wolę bardziej niż musztardę.
• Ja wolę majonez, nie musztardę.

But for a learner, the original order is the safest and most natural.

A rough pronunciation guide:

• wolę ≈ VOH-weh / VOH-leh with a nasalized final vowel
• musztardę ≈ moosh-TAR-deh with a nasalized final vowel

A few helpful points:

• w in Polish sounds like English v
• sz sounds like English sh
• j sounds like English y
• ę is a nasal vowel

In everyday speech, final ę is often pronounced less strongly nasal than learners expect, sometimes sounding close to e or em/en depending on context and speaker. But in careful pronunciation, it is still written and understood as ę.

Yes.

• majonez is masculine
• musztarda is feminine

This matters because gender affects case endings.

For example:

majonez

• nominative: majonez
• accusative: majonez

musztarda

• nominative: musztarda
• accusative: musztardę

Recognizing the dictionary form helps you predict changes:

• nouns ending in -a are often feminine
• many consonant-final nouns like majonez are masculine

Yes. Even if the Polish sentence uses niż (than), the most natural English translation is often:

• I prefer mayonnaise to mustard.

Learners should not try to match every Polish word one-for-one. The important pattern is:

• woleć X niż Y = to prefer X to Y

So when building Polish sentences, focus on the Polish structure, not the exact English preposition.

Yes, but you need the correct accusative forms.

For example:

• Wolę go niż ją. = I prefer him/it over her.
• Wolę to niż tamto. = I prefer this to that.

With things, pronouns can get tricky because Polish pronouns change for case and gender. For a beginner, it is often easier to practice first with full nouns:

• Wolę kawę niż herbatę.
• Wolę ser niż szynkę.