Školarina je skupa.

Because skupa has to agree with školarina, which is a feminine singular noun.

In Serbian, adjectives change form to match the noun’s:

• gender
• number
• case

Here the forms are:

• masculine: skup
• feminine: skupa
• neuter: skupo

So:

• stan je skup = the apartment is expensive
• školarina je skupa = the tuition is expensive
• vino je skupo = the wine is expensive

Je means is.

It is the 3rd person singular present tense of the verb biti = to be.

So the sentence is built like this:

• školarina = tuition
• je = is
• skupa = expensive

Literally: Tuition is expensive.

Normally, no.

In a full standard sentence like this, Serbian needs the verb je:

• Školarina je skupa.

Leaving it out would sound incomplete in standard Serbian.
You may sometimes hear shortened or headline-like speech without it, but that is not the normal form learners should use.

Školarina is feminine.

A very common clue is that it ends in -a, which often signals a feminine noun in Serbian.

Because it is feminine, the adjective also has the feminine form:

• školarina je skupa

If the noun were masculine, you would use skup.
If it were neuter, you would use skupo.

It is in the nominative singular.

That is because školarina is the subject of the sentence:

• Školarina je skupa.

The adjective skupa is also in the nominative feminine singular because it is a predicate adjective with biti and agrees with the subject.

No, Serbian word order is fairly flexible.

The neutral, most straightforward order is:

• Školarina je skupa.

But you can also say:

• Skupa je školarina.

This usually adds emphasis, roughly like:

• The tuition is expensive
• or even Tuition is what’s expensive

So the original sentence is the most neutral and basic version.

A helpful approximation for an English speaker is:

• Školarina ≈ shko-la-REE-na
• je ≈ ye
• skupa ≈ SKOO-pa

A few useful notes:

• š sounds like sh in shoe
• j sounds like English y in yes
• Serbian vowels are usually clear and short: a, e, i, o, u

So the whole sentence sounds roughly like:

shko-la-REE-na ye SKOO-pa

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

So:

• školarina je skupa

can mean:

• Tuition is expensive
• The tuition is expensive

The exact meaning depends on context.

Not in this sentence.

Here, the adjective must match školarina, which is feminine singular, so the correct form is skupa.

But skupo does exist. It can be:

1. the neuter singular adjective

   • more je skupo = the sea/coast is expensive

2. an adverb, meaning expensively

   • Plaćaš skupo. = You pay dearly / expensively.

So in Školarina je skupa, skupa is the only correct choice.

You make it negative by changing je to nije:

• Školarina nije skupa. = Tuition is not expensive.

This is very common with the verb biti:

• je → nije
• su → nisu

A few common ways are:

• Da li je školarina skupa?
• Je li školarina skupa?

Both mean:

• Is the tuition expensive?

In speech, intonation also helps show that it is a question.

Usually, yes.

Školarina refers to the money paid for schooling or studies, so tuition is usually the best translation.

Depending on context, it can also feel like:

• tuition fee
• school fee
• college tuition

So the exact English wording can vary a little, but tuition is expensive is a very natural translation.

The dictionary form is usually given as the masculine singular:

• skup = expensive

From that, you get:

• skup = masculine
• skupa = feminine
• skupo = neuter

So if you look the word up, you will usually find skup, even though the sentence uses skupa.