Moj brat uvek želi sladoled kada je vreme toplo.

Because moj has to agree with brat in gender, number, and case.

• brat = masculine, singular, nominative
• so the possessive adjective must also be masculine singular nominative: moj

Compare:

• moj brat = my brother
• moja sestra = my sister
• moje dete = my child

Serbian does not use articles like the or a/an.

So:

• brat can mean brother or the brother, depending on context
• sladoled can mean ice cream or the ice cream

English needs articles, but Serbian usually does not.

Želi is the 3rd person singular present tense of želeti (to want).

The subject is moj brat = my brother, which is he, so you use:

• ja želim = I want
• ti želiš = you want
• on/ona/ono želi = he/she/it wants

So moj brat želi = my brother wants.

Sometimes yes, but the nuance is a little different.

• želeti often sounds a bit more like to desire / to want
• hteti / hoće is very common and often means to want, but it can also mean will

So:

• Moj brat uvek želi sladoled = My brother always wants ice cream
• Moj brat uvek hoće sladoled = also possible in many contexts, a bit more everyday/conversational

In a learner sentence like this, želi is very clear and straightforward.

It is the direct object, so it is in the accusative case. But sladoled is a masculine inanimate noun, and for many masculine inanimate nouns, the accusative singular looks the same as the nominative singular.

So:

• nominative: sladoled
• accusative: sladoled

That is why the form does not visibly change.

Uvek means always.

In this sentence it modifies želi:

• Moj brat uvek želi sladoled = My brother always wants ice cream

Its position is fairly natural here, but Serbian word order is more flexible than English. You may also hear:

• Moj brat želi uvek sladoled
• Uvek moj brat želi sladoled (possible, but more marked or emphatic)

The version in your sentence is the most neutral and natural.

Kada means when and introduces a subordinate clause.

Here:

• kada je vreme toplo = when the weather is warm

So the sentence has:

1. the main clause: Moj brat uvek želi sladoled
2. the time clause: kada je vreme toplo

A shorter spoken variant is kad:

• Moj brat uvek želi sladoled kad je vreme toplo.

Both are correct.

Because vreme is a neuter noun.

The adjective must agree with vreme, so you get:

• toplo = neuter singular not
• topao = masculine singular

Compare:

• dan je topao = the day is warm
• voda je topla = the water is warm
• vreme je toplo = the weather is warm

This is because toplo is not simply describing the noun inside a noun phrase; it is part of a predicate after the verb je.

So the structure is:

• vreme = subject
• je = is
• toplo = warm

This is like:

• The weather is warm

If you wanted the adjective directly before the noun, you would say:

• toplo vreme = warm weather

So:

• kada je vreme toplo = when the weather is warm
• kada je toplo vreme = when it is warm weather / when the weather is warm

Both can work, but kada je vreme toplo is a very normal sentence structure.

Here it most naturally expresses a habitual action or a general truth.

• Moj brat uvek želi sladoled kada je vreme toplo. = Whenever the weather is warm, my brother wants ice cream.

The word uvek strongly suggests repetition or habit, not just a single moment happening now.

Not exactly. Želi specifically means wants.

If you want to say likes, Serbian would usually use voli:

• Moj brat voli sladoled. = My brother likes/loves ice cream.

So:

• želi sladoled = wants ice cream
• voli sladoled = likes ice cream

They are related in meaning, but not the same.

A rough pronunciation guide:

• želi ≈ ZHEH-lee

  • ž sounds like the s in measure
  • j sounds like English y

• sladoled ≈ slah-doh-LED

  • Serbian pronunciation is generally phonetic: words are usually pronounced as written

Also:

• uvek ≈ OO-vek
• kada ≈ KAH-dah
• vreme ≈ VREH-meh
• toplo ≈ TOH-ploh

Yes, absolutely.

• kada je vreme toplo = when the weather is warm
• kada je toplo = when it is warm / when it’s warm

The shorter version is very common in everyday speech. The version with vreme is a bit more explicit.

Serbian word order is fairly flexible, though some versions sound more neutral than others.

Neutral:

• Moj brat uvek želi sladoled kada je vreme toplo.

Possible alternatives:

• Kada je vreme toplo, moj brat uvek želi sladoled.
• Sladoled moj brat uvek želi kada je vreme toplo. (more emphasis on sladoled)

So yes, you can move parts around, but the original sentence is a very natural default order.