Glavni izvođač svira bis dok volonteri toče vodu.

A natural word-for-word breakdown is:

• glavni = main, lead
• izvođač = performer
• svira = plays / is playing
• bis = encore
• dok = while
• volonteri = volunteers
• toče = pour / are pouring / serve
• vodu = water

So the structure is basically:

• Glavni izvođač = the main performer
• svira bis = is playing an encore
• dok volonteri toče vodu = while volunteers are pouring water

Croatian normally does not use articles like the or a/an.

So glavni izvođač can mean:

• the main performer
• or sometimes just a main performer depending on context

In this sentence, English naturally uses the because main performer usually refers to a specific person already understood from the situation.

Croatian relies on:

• context
• word order
• adjectives
• the general situation

rather than articles.

Here, dok means while.

It links two actions happening at the same time:

• Glavni izvođač svira bis
• volonteri toče vodu

So: The main performer is playing an encore while the volunteers are pouring water.

Yes, dok can also mean until in other contexts. For example:

• Čekaj dok dođem. = Wait until I come.

In your sentence, because both clauses describe simultaneous ongoing actions, while is the right meaning.

Because this is the subject of the first clause, so both words are in the nominative singular masculine form.

• glavni agrees with izvođač
• izvođač is masculine singular
• so the adjective also appears in masculine singular nominative: glavni

This is the normal dictionary-like form for the subject.

Because volonteri is the subject of the second clause, so it has to be in the nominative plural.

• singular: volonter = volunteer
• plural nominative: volonteri = volunteers

By contrast, volontere would usually be accusative plural, which would be used for a direct object, not for the subject.

So:

• Volonteri toče vodu = The volunteers are pouring water
• not Volontere toče vodu

Because vodu is the direct object of toče.

The basic noun is:

• voda = water

But in this sentence, the volunteers are doing something to the water, so Croatian uses the accusative singular:

• nominative: voda
• accusative: vodu

This is very common with feminine nouns ending in -a:

• kava → kavu
• juha → juhu
• voda → vodu

Good question. Bis is also a direct object, but it does not change here because it is a masculine inanimate noun.

In Croatian, masculine inanimate nouns often have:

• nominative singular = accusative singular

So:

• bis = nominative
• bis = accusative

That is why you get:

• svira bis

but:

• toče vodu

So the two objects behave differently because the nouns belong to different grammatical patterns.

Both are in the present tense:

• svira = plays / is playing
• toče = pour / are pouring

Croatian does not have a separate progressive form like English is playing or are pouring. The plain present tense can cover both meanings, and context tells you which one fits best.

In this sentence, because the two actions are happening at the same time, English naturally translates them as:

• is playing
• are pouring

Also, both verbs are imperfective, which fits ongoing or repeated action well.

Točiti is often used for pouring or serving liquids, especially into cups, glasses, or containers.

So volonteri toče vodu suggests something like:

• serving water
• pouring water out for people
• filling cups or bottles

It is a very natural verb for drinks and other liquids in a practical setting.

No, Croatian word order is fairly flexible.

Your sentence has a very neutral order:

• Glavni izvođač svira bis dok volonteri toče vodu.

But you could also say:

• Dok volonteri toče vodu, glavni izvođač svira bis.

This means the same thing, but the emphasis shifts slightly. Starting with dok... puts the time/background part first.

Croatian often uses word order for:

• emphasis
• rhythm
• style
• what is already known vs. new information

The most useful sound notes are:

• č = like ch in church
• đ = a soft sound somewhat like dy/j; English does not match it perfectly

So:

• toče sounds roughly like TO-che
• izvođač sounds roughly like iz-VO-dyach

And a few more:

• glavni ≈ GLAHV-nee
• svira ≈ SVEE-ra
• bis = bees
• vodu ≈ VO-doo

The exact stress can vary, but those approximations will get you close enough to be understood.