Podgrijat ću juhu prije nego što djeca dođu kući.

It is the future tense in Croatian.

Croatian often forms the future with:

• the infinitive of the verb
• a short form of htjeti (ću, ćeš, će, ćemo, ćete, će)

So here:

• podgrijati = infinitive
• ću = I will

That gives podgrijat ću = I will reheat / warm up.

A very important detail: when ću comes after an infinitive ending in -ti, the final -i is usually dropped in writing:

• podgrijati → podgrijat ću
• pisati → pisat ću

If the auxiliary comes first, the full infinitive stays:

• Ja ću podgrijati juhu.

Because juhu is the accusative singular of juha.

• juha = nominative, the basic dictionary form
• juhu = accusative, used here because it is the direct object of the verb podgrijati

Croatian changes noun endings depending on their role in the sentence. Since the soup is what is being reheated, it goes into the accusative.

Prije nego što is a conjunction meaning before.

It introduces a subordinate clause:

• prije nego što djeca dođu kući = before the children come home

Yes, prije nego is also very common, especially in everyday speech:

• prije nego djeca dođu kući

In this sentence, što does not mean what. It is just part of the fixed conjunction.

Because in Croatian, after time expressions like:

• kad = when
• čim = as soon as
• nakon što = after
• prije nego što = before

the subordinate clause usually uses the present tense, even when the meaning is future.

So Croatian says:

• Podgrijat ću juhu prije nego što djeca dođu kući.

not usually:

• ...prije nego što će djeca doći kući.

This is very normal Croatian grammar. English also does something similar:

• I’ll do it before they come home not before they will come home

This is about aspect.

• doći → perfective = to come / arrive as a completed event
• dolaziti → imperfective = to be coming / to come repeatedly / habitually

In this sentence, the idea is a single completed arrival:

• the children will arrive home

So Croatian uses the perfective verb:

• dođu

If you said dolaze, it would sound more like a repeated or ongoing action, not one specific future arrival.

Djeca means children, and it behaves as a plural noun in agreement.

So you get:

• djeca dođu
• djeca su došla
• mala djeca

Even though its form may look unusual, you should learn it as the normal word for children, with plural agreement.

Its singular is:

• dijete = child

So:

• dijete dođe = the child comes
• djeca dođu = the children come

Because kući is a very common fixed form meaning home after verbs of motion.

So:

• doći kući = to come home
• ići kući = to go home
• vratiti se kući = to return home

This works a bit like English go home, where no preposition is needed.

Historically, kući is a case form of kuća (house), but learners should mainly remember it as the normal expression for home in motion phrases.

Compare:

• Idem kući. = I’m going home.
• Ulazim u kuću. = I’m going into the house.

The first is the idiomatic home expression; the second is more literally about entering a house.

Yes. Croatian word order is fairly flexible, but the little word ću is a clitic, so it tends to go in second position in its clause.

Your sentence can be rearranged, for example:

• Podgrijat ću juhu prije nego što djeca dođu kući.
• Juhu ću podgrijati prije nego što djeca dođu kući.
• Prije nego što djeca dođu kući, podgrijat ću juhu.

All of these are natural, with slightly different emphasis.

A useful rule:

• if ću comes after the verb, the infinitive is shortened: podgrijat ću
• if ću comes before the verb, the full infinitive stays: ću podgrijati

It changes the meaning from general heating to warming up / reheating.

Compare:

• grijati = to heat, to warm
• podgrijati = to warm up again, reheat

So podgrijati juhu is a very natural way to say reheat the soup or warm the soup up.

This is a common feature of Croatian verbs: prefixes often add a more specific meaning, and they also often affect aspect.

No—both are normal. They are just different word orders.

• Podgrijat ću juhu = verb first
• Ja ću podgrijati juhu = subject + auxiliary first

The first one sounds natural and compact. The second may put a little more emphasis on I, especially if ja is actually spoken.

The main thing to remember is:

• after the verb: podgrijat ću
• after ću: podgrijati