Odvojeno sakupljanje počinje pre ponovne upotrebe.

The subject is odvojeno sakupljanje.

• sakupljanje = the main noun
• odvojeno = an adjective describing it

So the sentence is built like:

• Odvojeno sakupljanje = subject
• počinje = verb
• pre ponovne upotrebe = time expression meaning before reuse

Because it agrees with sakupljanje, which is a neuter singular noun.

In Serbian, adjectives change their endings to match the noun in:

• gender
• number
• case

Here:

• sakupljanje is neuter singular
• so the adjective also appears in neuter singular: odvojeno

Compare:

• odvojen = masculine
• odvojena = feminine
• odvojeno = neuter

So odvojeno sakupljanje means separate collection or separated collecting, with normal adjective-noun agreement.

It is a noun, specifically a verbal noun.

It comes from the verb sakupljati = to collect / to gather.

The ending -anje often forms nouns that are similar to English -ing words:

• čitati → čitanje = reading
• pisati → pisanje = writing
• sakupljati → sakupljanje = collecting / collection

So in this sentence, sakupljanje is not the verb. The actual verb is počinje.

Because the subject odvojeno sakupljanje is singular.

Even though the idea may feel broad in English, grammatically the subject is one singular noun phrase:

• sakupljanje = one act/process/concept of collection

So Serbian uses:

• počinje = begins / starts for he/she/it

If the subject were plural, the verb would also be plural.

Počinje is the present-tense form of the imperfective verb počinjati.

This is natural when talking about:

• a general process
• something habitual
• a statement of how things normally work

By contrast, počne comes from the perfective verb početi, which is more about a single completed beginning.

So in a general statement like this, počinje is the more expected choice.

A simple way to remember it:

• počinje = is beginning / begins in general
• počne = begins once, as a completed event

Because pre takes the genitive case.

The basic form is:

• ponovna upotreba = nominative

After pre, it changes to genitive:

• pre ponovne upotrebe

So this is a normal case pattern:

• pre + genitive = before + noun

Other examples:

• pre škole = before school
• pre ručka = before lunch
• pre početka = before the beginning

Because ponovne is the genitive singular feminine form of the adjective ponovan / ponovna / ponovno.

The noun upotreba is:

• feminine
• singular
• here in the genitive case, because it follows pre

So the adjective must match it:

• nominative: ponovna upotreba
• genitive: ponovne upotrebe

Both words change together:

• ponovna → ponovne
• upotreba → upotrebe

Upotreba is a noun meaning use.

With ponovna, it becomes ponovna upotreba = reuse or literally repeated use / use again.

So:

• upotreba = use
• ponovna upotreba = reuse

This is a common way Serbian builds meanings: adjective + noun, rather than always using a single compound word.

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

The given sentence has a neutral, straightforward order:

• Odvojeno sakupljanje počinje pre ponovne upotrebe.

But you could also say:

• Pre ponovne upotrebe počinje odvojeno sakupljanje.

That version puts more focus on the time relation before reuse.

Even so, the original order is probably the most neutral and easiest for learners.

Yes, that is a good observation.

In standard Serbian, pre is the usual word for before.

In Croatian and in many Bosnian varieties, prije is more common.

So:

• Serbian: pre
• Croatian: prije

A learner should recognize both, but in a clearly Serbian sentence, pre is the expected form.

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

Whether something is definite or indefinite is usually understood from:

• context
• word order
• emphasis
• the general situation

So odvojeno sakupljanje can mean:

• separate collection
• the separate collection
• sometimes even separate collecting

depending on context.

This is very normal in Serbian and other Slavic languages.

A few parts may stand out to an English speaker:

• č in počinje sounds like ch in church
• nj in počinje sounds roughly like ny in canyon
• lj in sakupljanje sounds roughly like a soft ly
• Serbian spelling is quite phonetic, so words are usually pronounced as written

Very rough English-style approximations:

• Odvojeno ≈ od-vo-YE-no
• sakupljanje ≈ sa-KOO-PLYA-nye
• počinje ≈ PO-chee-nye
• pre ≈ preh
• ponovne upotrebe ≈ po-NOV-ne oo-po-TRE-be

These are only approximations, but they can help you get close.