Radijski prijemnik, pištaljka i komplet za hitne slučajeve su ovdje.

Because the subject is a list of three things:

• radijski prijemnik
• pištaljka
• komplet za hitne slučajeve

Together, they form a plural subject, so Croatian uses the plural form of to be:

• je = is (singular)
• su = are (plural)

So ... su ovdje means ... are here.

They are in the nominative case, because they are the subject of the sentence — the things that are here.

You can think of the basic structure as:

• [subject] + su + ovdje
• [these things] + are + here

So:

• radijski prijemnik = nominative singular
• pištaljka = nominative singular
• komplet = nominative singular

Even though each noun is singular, the whole list is plural, which is why the verb is su.

After the preposition za, Croatian usually uses the accusative case when it means for.

So:

• za = for
• hitne slučajeve = emergencies / emergency situations, in the accusative plural

The dictionary forms are:

• hitan = urgent / emergency
• slučaj = case, situation

In this phrase:

• hitne is the accusative plural form of hitan
• slučajeve is the accusative plural form of slučaj

So komplet za hitne slučajeve literally means something like a kit for emergency situations.

Radijski prijemnik is a more formal or descriptive way to say radio receiver.

• radio is the common everyday word for radio
• prijemnik means receiver
• radijski means radio-related

So:

• radijski prijemnik = radio receiver

A learner may hear both in real life, but this sentence uses the more precise expression.

Radijski is an adjective meaning radio, radio-related, or of radio.

The ending -ski is a common Croatian adjective ending. Here it turns the idea of radio into an adjective that describes prijemnik.

Because prijemnik is:

• masculine
• singular
• nominative

the adjective also appears in the masculine singular nominative form:

• radijski prijemnik

This is normal Croatian adjective agreement: adjectives agree with the noun in gender, number, and case.

Croatian does not have articles like English a/an and the.

So:

• pištaljka can mean a whistle or the whistle
• komplet can mean a kit or the kit
• radijski prijemnik can mean a radio receiver or the radio receiver

The exact meaning depends on context.

That is one of the biggest differences English speakers notice when learning Croatian.

Ovdje means here.

Yes, Croatian word order is fairly flexible, so you may also see:

• Radijski prijemnik, pištaljka i komplet za hitne slučajeve ovdje su.
• Ovdje su radijski prijemnik, pištaljka i komplet za hitne slučajeve.

The most natural version usually depends on what you want to emphasize.

In your sentence, su ovdje is a very normal way to say are here.

I means and.

Croatian lists work much like English lists:

• item 1, item 2 i item 3

So:

• Radijski prijemnik, pištaljka i komplet za hitne slučajeve

means:

• A radio receiver, a whistle, and an emergency kit

This is standard list structure in Croatian.

Pištaljka means whistle — usually the small object you blow into to make a loud sound.

It is a feminine noun, which you can often recognize from the -a ending in the nominative singular.

So here:

• pištaljka = whistle

It is one of the three things named in the subject of the sentence.

Not really. Even though komplet may remind an English speaker of complete, here komplet is a noun, not an adjective.

It means:

• set
• kit
• complete kit/set

So komplet za hitne slučajeve means:

• emergency kit
• literally, kit for emergency situations

This is a good example of why similar-looking words between languages do not always work the same way grammatically.

A rough English-friendly pronunciation would be:

RAH-dee-yee-skee pree-YEM-neek, peesh-TAHL-yka ee KOM-plet za HEET-neh sloo-CHA-yeh-veh soo OV-dyeh

A few useful pronunciation notes:

• j is pronounced like English y
• lj is a soft sound, somewhat like ly
• č sounds like ch
• ć is also a ch-like sound, but softer
• dje in ovdje sounds roughly like dye

Croatian spelling is quite regular, so pronunciation is usually more predictable than in English.