Međubibliotečka pozajmica će početi u biblioteci.

Međubibliotečka pozajmica literally means something like interlibrary loan.

The adjective međubibliotečka is built from:

• među- = inter-, between
• biblioteka = library
• the adjective ending -čka

So međubibliotečka means interlibrary or between libraries.

It agrees with pozajmica because pozajmica is feminine singular, so the adjective also appears in the feminine singular form.

Pozajmica is a noun meaning loan or borrowing.

In this sentence, it is the subject of the sentence:

• Međubibliotečka pozajmica = the interlibrary loan

Grammatically:

• it is feminine
• singular
• in the nominative case, because it is the thing that will begin

A learner may also notice that Serbian can use related words depending on context, but here pozajmica is the noun chosen in the sentence.

Yes. Će početi is the future tense.

Serbian often forms the future with:

• the clitic će
• plus the infinitive of the verb

Here:

• će = future marker, roughly will
• početi = to begin

So:

• će početi = will begin

This is a very common future pattern in Serbian.

In Serbian, the future can be written in more than one common way depending on word order.

With the verb početi, you may see:

• počeće
  or
• će početi

Both express will begin.

In your sentence, the future marker comes before the infinitive:

• će početi

That is completely normal and very common.

Početi is a perfective verb meaning to begin / to start.

That matters because Serbian aspect is important:

• perfective verbs focus on a completed event or single occurrence
• imperfective verbs focus on process, repetition, or duration

Since beginning is naturally a single event, Serbian usually uses the perfective verb početi here.

So će početi means it will start / it will begin, focusing on the start as a whole event.

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

The noun biblioteka changes like this:

• nominative: biblioteka
• locative: biblioteci

So:

• u biblioteci = in the library

This is one of the most common case patterns in Serbian:

• u + locative for location

Biblioteci is in the locative singular.

You know this because:

1. the preposition u is used
2. here u means in a place, not movement into it
3. location with u normally takes the locative

Compare:

• u biblioteci = in the library → location, so locative
• u biblioteku = into the library → movement/direction, so accusative

That location-vs-direction contrast is very important in Serbian.

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

So biblioteci can mean:

• in the library
• in a library

The exact meaning depends on context.

The same is true for međubibliotečka pozajmica:

• it could mean the interlibrary loan
• or an interlibrary loan

English needs an article, but Serbian usually does not.

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

The sentence you have is:

• Međubibliotečka pozajmica će početi u biblioteci.

That is a natural neutral order.

But Serbian can move parts around for emphasis, for example:

• U biblioteci će početi međubibliotečka pozajmica.
• Počeće međubibliotečka pozajmica u biblioteci.

These versions may sound more marked or emphasize a different part of the sentence, but they are still understandable.

One thing to remember: će is a clitic, so it tends to appear in the second position of the clause.

These letters are important in Serbian pronunciation:

• đ as in Međubibliotečka
  Pronounced somewhat like the j in judge, but usually softer.

• č as in Međubibliotečka and početi
  Pronounced like ch in church, but often a bit firmer.

• ć as in biblioteci
  A softer sound than č. English does not have an exact match, but it may sound a bit like a very soft ty/ch sound.

Also:

• j in Serbian is pronounced like English y in yes
• stress is not marked in normal writing, so learners usually have to hear the word or learn it separately

In this sentence, u biblioteci most naturally means in the library as the location where the event begins.

So it answers the question:

• Where will it begin?
• U biblioteci.

Grammatically, it is a prepositional phrase of location.

A learner should also notice that even if the English translation is already given, the Serbian structure is very straightforward here:

• subject: Međubibliotečka pozajmica
• future verb: će početi
• place: u biblioteci