On voli šećer u kafi, ali ja ne volim šećer.

Because the verb changes depending on the subject.

The verb here is voleti / voljeti (to love, to like). In the present tense:

• ja volim = I like
• ti voliš = you like
• on/ona/ono voli = he/she/it likes
• mi volimo = we like
• vi volite = you like
• oni/one/ona vole = they like

So:

• On voli = He likes
• Ja ne volim = I do not like

This is one of the most basic Serbian verb patterns: the ending tells you who the subject is.

No. Serbian often drops subject pronouns because the verb ending already shows who the subject is.

So these are both natural:

• On voli šećer u kafi, ali ja ne volim šećer.
• Voli šećer u kafi, ali ne volim šećer.

The full pronouns on and ja are often used for emphasis or contrast. In this sentence, they help highlight the difference:

• He likes sugar in coffee, but I do not like sugar.

So the pronouns are not strictly necessary, but they are very natural here because of the contrast.

Ali means but.

It connects two contrasting ideas:

• On voli šećer u kafi = He likes sugar in coffee
• ali ja ne volim šećer = but I do not like sugar

It is a very common conjunction in Serbian.

In Serbian, negation with verbs is usually made by putting ne before the verb.

So:

• volim = I like
• ne volim = I do not like

More examples:

• znam = I know

• ne znam = I do not know

• radim = I work
• ne radim = I do not work

So ne is the normal negation particle.

Because after the preposition u when it means in, Serbian uses the locative case.

The noun kafa (coffee) changes form:

• base form: kafa
• after u: u kafi = in the coffee

So:

• šećer u kafi = sugar in coffee

This is a very important Serbian pattern:

• u + locative for location: in
• na + locative for location: on, at

Examples:

• u kući = in the house
• u školi = in school
• na stolu = on the table

Serbian does not have articles like a and the, so u kafi can depend on context.

It can mean:

• in the coffee
• in coffee

In this sentence, English would most naturally say in coffee or in his coffee, but the Serbian form itself does not mark that difference with an article.

That is normal in Serbian: nouns usually appear without anything corresponding to a/an/the.

Because in both places it is the direct object of voleti/voleti in an affirmative/negative statement, and the normal case here is the accusative.

For the noun šećer (sugar), the accusative singular looks the same as the nominative singular because it is an inanimate masculine noun.

So:

• šećer = sugar
• voli šećer = likes sugar
• ne volim šećer = I do not like sugar

Many masculine inanimate nouns behave like this: nominative and accusative singular are identical.

It can mean either to love or to like, depending on context.

In this sentence, voli šećer u kafi is best understood as likes sugar in coffee, not loves sugar in coffee in a dramatic sense.

Serbian voleti is wider in meaning than English love. It is commonly used where English would often say like:

• Volim kafu. = I like coffee.
• Volim muziku. = I like music.

Of course, it can also mean love in stronger contexts:

• Volim te. = I love you.

Yes. Serbian often leaves possession unstated when it is obvious from context.

So On voli šećer u kafi literally means He likes sugar in coffee, but in natural English we often interpret it as He likes sugar in his coffee.

Serbian does not need to say his unless it matters. If you wanted to make it explicit, you could say something like u svojoj kafi (in his own coffee), but that would be more specific and not necessary here.

Yes. Serbian word order is more flexible than English word order, because cases and verb endings carry a lot of grammatical information.

The given sentence is very natural:

• On voli šećer u kafi, ali ja ne volim šećer.

But you could also hear variations such as:

• On voli u kafi šećer, ali ja ne volim šećer.
• Šećer u kafi on voli, ali ja ne volim šećer.

These alternatives may sound more marked or emphasize a different part of the sentence. For learners, the original order is the safest and most neutral.

These letters are very important in Serbian pronunciation.

• š sounds like sh in shoe

  • šećer ≈ SHEH-cher or SHEH-tyer depending on accent and how you approximate ć

• ć is a soft consonant, somewhat like a very soft ch/t sound. English does not have an exact equivalent.

  • In šećer, it is softer than č.

• j sounds like English y in yes

  • ja = ya
  • voli is pronounced roughly VOH-lee

A rough learner-friendly pronunciation of the whole sentence could be:

• On VOH-lee SHEH-ćer oo KAH-fee, AH-lee ya neh VOH-leem SHEH-ćer.

This is only approximate, but it helps at the beginning.

This is a very common learner question.

• č is a harder sound, closer to ch in church
• ć is softer, produced further forward in the mouth

In šećer, the letter is ć, not č.

For many English speakers, this difference is hard to hear and pronounce at first, but it matters in standard Serbian spelling and pronunciation. Even if your pronunciation is not perfect right away, it is good to notice that Serbian treats them as different letters.

Because Serbian does not use articles like English a/an and the.

So šećer can mean:

• sugar
• the sugar
• some sugar

The exact meaning comes from context.

That is why:

• On voli šećer u kafi naturally means He likes sugar in coffee
• ja ne volim šećer naturally means I don’t like sugar

English requires an article or zero article depending on the noun and meaning, but Serbian does not.

Yes, literally it means in coffee or in the coffee.

In this sentence, the natural interpretation is the common one: putting sugar into coffee. So šećer u kafi means sugar in coffee.

If you wanted to say with coffee in a broader sense, Serbian might use other structures depending on the situation. But here u kafi is exactly the normal way to express sugar being added into the coffee.

This sentence is fine in standard Serbian and does not hinge strongly on an ekavian/ijekavian difference in the words shown here. The key forms here are standard and widely understandable.

One thing learners may notice is that the infinitive of to love/like can be given as:

• voleti in Serbian usage
• voljeti in some other South Slavic standards or varieties

But the present tense forms like voli and volim are what matter in this sentence, and they are straightforward for learners.

So for practical purposes, you can simply learn the sentence as standard Serbian:

• On voli šećer u kafi, ali ja ne volim šećer.

Yes, but that changes the meaning slightly.

• Ja ne volim šećer. = I do not like sugar.
• Ja ne volim šećer u kafi. = I do not like sugar in coffee.

The original sentence says something broader in the second part: the speaker does not like sugar at all, or at least is not presenting the dislike as only about coffee.

If you add u kafi in the second clause, then the contrast becomes specifically about sugar in coffee.

Because it describes what kind of preference is meant: sugar in coffee.

So:

• šećer u kafi = sugar in coffee

This works similarly to English noun phrases, where a prepositional phrase can follow a noun and narrow its meaning.

In practice, the Serbian sentence is saying:

• He likes sugar in coffee
• but I do not like sugar

That contrast is clearer with u kafi placed right after šećer in the first clause.