Osiguranje i tehnički pregled su skupi.

Su is the 3rd person plural present tense of biti (to be).

So:

• ja sam = I am
• ti si = you are
• on/ona/ono je = he/she/it is
• mi smo = we are
• vi ste = you are
• oni/one/ona su = they are

In Osiguranje i tehnički pregled su skupi, the subject is made of two things joined by i:

• osiguranje = insurance
• tehnički pregled = technical inspection

Because the subject is plural in meaning, Serbian uses su = are.

Because the sentence has a compound subject:

• osiguranje
• tehnički pregled

They are joined by i (and), so together they mean two things, not one. That is why the predicate adjective must also be plural:

• skup = expensive (masculine singular)
• skupa = expensive (feminine singular)
• skupo = expensive (neuter singular)
• skupi = expensive (plural, here masculine/mixed)

So:

• Tehnički pregled je skup. = The technical inspection is expensive.
• Osiguranje je skupo. = Insurance is expensive.
• Osiguranje i tehnički pregled su skupi. = Insurance and the technical inspection are expensive.

This is a very common question. The short answer is: when Serbian has a mixed-gender compound subject, the adjective usually goes into masculine plural.

Here the two nouns are:

• osiguranje — neuter singular
• tehnički pregled — masculine singular

When you combine them with i, Serbian normally uses masculine plural agreement, so:

• su skupi

That is why you do not say:

• *su skupa
• *su skupo

because the whole subject is plural, and mixed groups typically default to masculine plural.

They are in the nominative case, because they are the subject of the sentence.

You can recognize that the sentence is built like this:

• Osiguranje i tehnički pregled = subject
• su = verb
• skupi = predicate adjective

So both nouns are in their dictionary/basic form here:

• osiguranje
• tehnički pregled

Tehnički pregled literally means technical inspection, but in everyday use it usually refers to the vehicle inspection / roadworthiness inspection that a car must pass.

So in context, this sentence most naturally means something like:

• Insurance and the vehicle inspection are expensive.

The phrase is made of:

• tehnički = technical
• pregled = inspection, examination, check

Together they form a fixed everyday expression.

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

So:

• osiguranje can mean insurance, the insurance, or sometimes an insurance policy, depending on context.
• tehnički pregled can mean technical inspection or the technical inspection.

You understand the exact meaning from the situation, not from an article.

That is why Serbian learners of English often struggle with articles, and English speakers learning Serbian often expect them to be there when they are not.

Yes, depending on context.

In Serbian, osiguranje is a broad noun. It can refer to:

• insurance in general
• an insurance policy
• the insurance payment/coverage in context

In this sentence, it most likely means car insurance or insurance costs, since it appears together with tehnički pregled.

So the natural English meaning depends on context, even though the Serbian form stays the same.

Yes. Serbian word order is more flexible than English word order.

All of these are possible, depending on emphasis:

• Osiguranje i tehnički pregled su skupi.
• Skupi su osiguranje i tehnički pregled.

The first one is the most neutral.
The second one puts more emphasis on skupi (expensive).

Even though the word order changes, the meaning stays basically the same.

Because it agrees with pregled, which is:

• masculine
• singular
• nominative

So the adjective must also be masculine singular nominative:

• tehnički pregled = technical inspection

If the noun changed, the adjective would change too. For example:

• tehnička kontrola = technical control/check (feminine)
• tehničko pitanje = technical question (neuter)

So tehnički is simply the correct agreeing form for pregled.

Yes. I means and.

So:

• osiguranje i tehnički pregled = insurance and technical inspection

It is one of the most basic Serbian conjunctions.

Be careful with pronunciation, though: Serbian i is pronounced like ee in see, not like English eye.

No, not in a normal complete sentence like this.

In present-tense Serbian, the verb biti (to be) is usually required in this kind of predicate:

• Osiguranje i tehnički pregled su skupi.

Leaving out su would sound incomplete or ungrammatical in standard Serbian.

So unlike in some languages where to be can disappear in the present tense, here it stays.

A simple pronunciation guide:

• Osiguranje ≈ oh-see-GOO-ra-nye
• i ≈ ee
• tehnički ≈ TEHH-nich-kee
• pregled ≈ PREH-gled
• su ≈ soo
• skupi ≈ SKOO-pee

A rough full reading:

oh-see-GOO-ra-nye ee TEHH-nich-kee PREH-gled soo SKOO-pee

A few useful notes:

• nj in osiguranje sounds like the ny in canyon.
• č in tehnički sounds like ch in church.
• Serbian spelling is very phonetic, so words are usually pronounced much more closely to how they are written than in English.

Because Serbian adjectives must agree with the noun in gender, number, and case.

Compare:

• Osiguranje je skupo.

  • osiguranje is neuter singular
  • so the adjective is skupo

• Tehnički pregled je skup.

  • pregled is masculine singular
  • so the adjective is skup

• Osiguranje i tehnički pregled su skupi.

  • now the subject is plural and mixed-gender
  • so the adjective becomes skupi

This is one of the biggest structural differences from English, where expensive never changes form.

It can be either, depending on context.

Without articles, Serbian often leaves this open. The sentence could mean:

• Insurance and the technical inspection are expensive in general
• The insurance and the inspection for a particular vehicle are expensive
• More loosely, insurance and inspection cost a lot

In real-life conversation, if someone is talking about owning a car, this sentence will usually be understood in that practical sense.