Služba za izgubljeni prtljag je u holu za dolaske.

Here služba means something like service, office, or department.

So služba za izgubljeni prtljag is not just an abstract service. In an airport context, it usually refers to the lost luggage office/desk.

Grammatically, služba is a feminine singular noun.

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

So:

• služba can mean a service or the service
• holu can mean a hall or the hall

Which one is meant depends on context. In this sentence, the meaning is naturally definite in English, so we translate it with the.

The sentence uses several different cases:

• Služba — nominative singular
  It is the subject of the sentence.

• za izgubljeni prtljag — accusative
  After za, this phrase means for lost luggage.

• u holu — locative singular
  After u, when it means in a place, Serbian uses the locative.

• za dolaske — accusative plural
  Again, za here means for, as in the hall for arrivals.

So the structure is:

• subject in nominative
• location with u + locative
• purpose/function with za + accusative

Because prtljag is:

• masculine
• singular
• inanimate
• here used in the accusative

For masculine inanimate nouns, the accusative singular looks the same as the nominative singular. That is why you get:

• izgubljeni prtljag

and not something like izgubljenog prtljaga

The adjective izgubljeni has to agree with prtljag in gender, number, and case.

A useful comparison:

• vidim izgubljeni kofer — I see the lost suitcase
• vidim izgubljenu torbu — I see the lost bag

The adjective changes because kofer is masculine, while torba is feminine.

Because prtljag is usually treated as a mass noun, much like English luggage or baggage.

So Serbian normally says:

• izgubljeni prtljag — lost luggage

even if it refers to several bags or suitcases.

If you want to count individual items, Serbian would use other nouns such as:

• koferi — suitcases
• torbe — bags

But in airport language, prtljag in the singular is the standard choice.

Je is the 3rd person singular present of biti, meaning to be.

So:

• Služba ... je u holu ... = The office/service is in the hall ...

In normal Serbian sentences like this, the present tense of to be is usually expressed, unlike in Russian, where it is often omitted in the present.

So je is completely normal and necessary here.

Because u can take different cases depending on meaning:

• u + locative = in a place, static location
• u + accusative = into a place, movement toward it

Here the meaning is location, not movement:

• je u holu — is in the hall

So we use the locative form holu.

Compare:

• On je u holu. — He is in the hall.
• On ide u hol. — He is going into the hall.

Here za again means for in the sense of intended for or connected with.

So:

• hol za dolaske = hall for arrivals = arrivals hall

The noun dolaske is the accusative plural of dolazak.

The plural is natural here because an airport deals with arrivals in general, not just one single arrival.

You can compare:

• hol za dolaske — arrivals hall
• hol za odlaske — departures hall

Yes. Serbian word order is more flexible than English word order because the case endings show grammatical relationships.

The original sentence is neutral and natural:

• Služba za izgubljeni prtljag je u holu za dolaske.

But you could also say:

• U holu za dolaske je služba za izgubljeni prtljag.

That version puts more focus on the location.

So the original order is a good default, but it is not the only possible order.

Yes, it is a natural and normal sentence, especially in an airport context.

A few common alternatives are also possible, depending on style:

• Služba za izgubljeni prtljag je u hali za dolaske.
  Using hala instead of hol

• Služba za izgubljeni prtljag je na dolascima.
  A shorter, more contextual way to say it, roughly at arrivals

The original sentence is clear and standard.

A rough English-friendly guide:

• služba ≈ SLOOZH-ba
  The letter ž sounds like the s in measure

• izgubljeni ≈ eez-GOOB-lye-nee
  The lj is a soft sound, somewhat like the lli in million for many speakers

• prtljag ≈ PRT-lyag
  This one is hard for English speakers because Serbian can have a syllabic r. Try not to add a strong vowel before the r

• holu ≈ HOH-loo
• dolaske ≈ doh-LAHS-keh

You do not need perfect pronunciation right away. The hardest parts for most learners are:

• ž
• lj
• the beginning of prtljag

Very literally, it is:

• Služba — service / office
• za — for
• izgubljeni prtljag — lost luggage
• je — is
• u holu — in the hall
• za dolaske — for arrivals

So the literal structure is:

Service for lost luggage is in hall for arrivals.

That is why the natural English version becomes:

The lost luggage office is in the arrivals hall.