Oni će večeras doći sa cvećem.

This is the future tense in Serbian.

It is formed with:

• the short form of hteti (ću, ćeš, će, ćemo, ćete, će)
• plus the infinitive of the main verb

So here:

• oni = they
• će = will
• doći = to come

Together, oni će doći = they will come.

In Serbian, the future tense is often written as:

• subject + short auxiliary + infinitive

So:

• Oni će doći = They will come

This is normal and correct.

You may also see forms where the auxiliary attaches in different constructions, especially when there is no explicit subject, but in a sentence like this, oni će doći is the standard pattern a learner should recognize.

Not always.

Serbian often omits subject pronouns because the verb form usually makes the subject clear enough from context. So you could also say:

• Večeras će doći sa cvećem.

That can still mean They will come tonight with flowers, depending on context.

However, oni may be included:

• for emphasis
• for contrast
• for clarity

So oni is grammatical, but not always required.

This is about aspect, which is very important in Serbian.

• doći is perfective
• dolaziti is imperfective

Doći is used when talking about a single completed arrival: they will arrive / they will come.

In this sentence, the idea is a specific future event, so doći is the natural choice.

If you used dolaziti, it would suggest repeated action, process, or a different nuance, and it would usually not fit as well here.

Večeras means tonight / this evening.

It refers specifically to the evening of today.

So:

• večeras = tonight
• svake večeri = every evening
• uveče = in the evening

In this sentence, večeras tells you when they will come.

Cvećem is in the instrumental case.

After the preposition sa or s meaning with, Serbian normally uses the instrumental:

• sa cvećem = with flowers

Base form:

• cveće = flowers / flower(s), as a collective noun

Instrumental form:

• cvećem

So the sentence uses instrumental because sa requires it.

Both s and sa can mean with.

In many cases, sa is used for easier pronunciation, especially before certain consonants or consonant clusters.

So:

• s prijateljem = with a friend
• sa cvećem = with flowers

Here, sa cvećem sounds more natural and easier to pronounce than s cvećem, though you may hear variation in real speech.

This is a very common learner question.

Cveće is a collective noun. It often corresponds to English flowers or flower(s), even though it behaves grammatically like a singular neuter noun.

So:

• nominative: cveće
• instrumental: cvećem

Even though English uses a regular plural noun here, Serbian uses cveće, which is a collective form.

Yes. Serbian word order is fairly flexible.

The sentence:

• Oni će večeras doći sa cvećem

could also appear as:

• Večeras će oni doći sa cvećem
• Sa cvećem će oni doći večeras
• Oni će doći večeras sa cvećem

These versions are not all identical in emphasis, but they are grammatically possible.

The original order sounds natural and neutral:

• oni = who
• će doći = what will happen
• večeras = when
• sa cvećem = with what

Doći is pronounced approximately like DO-chee, but with a softer sound than English ch.

A rough guide:

• do = like do in English
• ći = a soft ch + ee

The letter ć is a soft consonant, different from č.

• ć = softer
• č = harder

English does not have a perfect equivalent, so learners usually need some listening practice to hear and produce the difference clearly.

The negative is made by putting ne before the auxiliary:

• Oni neće večeras doći sa cvećem.

That means:

• They will not come tonight with flowers.

Notice that:

• će becomes neće in the negative future form.

A simple yes/no question can be made like this:

• Hoće li oni večeras doći sa cvećem?

This means:

• Will they come tonight with flowers?

Another conversational possibility in speech is to rely on intonation, but Hoće li... is a very standard way to form the question.

Usually it means they are coming with flowers, so the natural interpretation is that they are bringing or carrying flowers with them.

Depending on context, it could also simply describe accompaniment, but in ordinary usage most people would understand:

• They will come bringing flowers / They will arrive with flowers.

So the phrase strongly suggests the flowers will be with them when they come.