Learn Hardcore Croatian: Roditelji su ponosni kad brat ima dobru ocjenu. - The parents are proud when my brother has a good grade.

The word su is a short form (clitic) of the verb biti (to be), 3rd person plural. Croatian clitics normally want to stand in second position in the clause.

In Roditelji su ponosni:

Roditelji = first element (subject)
su = clitic, so it goes right after the first element
ponosni = predicate adjective

You normally would not say Roditelji ponosni su in neutral speech. That word order sounds unusual or poetic/emphatic.

So:

Roditelji su ponosni. = normal sentence
Roditelji ponosni su. = very marked / only for special emphasis or style

Why is it ponosni and not ponosan or ponosna?

The adjective ponosan (proud) must agree with the noun it describes in gender and number.

Roditelji (parents) is grammatically masculine plural in Croatian. Any mixed or unspecified group of people defaults to masculine plural.
The masculine plural form of ponosan in the nominative case is ponosni.

Examples:

Singular:

masculine: ponosan otac – a proud father
feminine: ponosna majka – a proud mother
neuter: ponosno dijete – a proud child

Plural:

masculine plural: ponosni roditelji – proud parents
feminine plural: ponosne mame – proud mums

Because roditelji is masculine plural, you must use ponosni.

Why is it just brat and not the brother or my brother? And why isn’t it brata?

Two issues here:

No “the” or “a” in Croatian
Croatian has no articles like the or a. Whether you mean a brother, the brother, or my brother is decided by context or by adding a possessive:

brat – a/the brother (context decides which)
moj brat – my brother
naš brat – our brother

Case: why “brat” and not “brata”?
In brat ima dobru ocjenu:
- brat is the subject of the verb ima (has).
- Subjects in their basic form take the nominative case.
- The nominative singular is brat.

Brata is the accusative (or genitive) form and is used when brother is the object, for example:

Vidim brata. – I see (my) brother.

Here, brother is the one who has the grade (subject), so we use brat, not brata.

Why is it brat ima and not brat imaju?

The verb must agree with the subject in person and number.

brat = he → 3rd person singular
The verb imati (to have) in 3rd person singular is ima.

Present tense of imati:

(ja) imam – I have
(ti) imaš – you (sg) have
(on/ona/ono) ima – he/she/it has
(mi) imamo – we have
(vi) imate – you (pl/formal) have
(oni/one/ona) imaju – they have

Imaju is plural (they have). You’d use it with a plural subject:

Braća imaju dobru ocjenu. – The brothers have a good grade.

Why is it dobru ocjenu and not dobra ocjena?

Because dobru ocjenu is in the accusative case, which is used for the direct object of the verb.

In brat ima dobru ocjenu:

The verb: ima – has
Direct object: ocjenu – (a) grade, what he has

The noun ocjena is feminine:

nominative singular (subject form): ocjena
accusative singular (object form): ocjenu

The adjective dobar (good) must agree with ocjenu:

feminine nominative singular: dobra ocjena
feminine accusative singular: dobru ocjenu

Compare:

Dobra ocjena je važna. – A good grade is important. (subject → nominative)
Brat ima dobru ocjenu. – (My) brother has a good grade. (object → accusative)

So here the correct form is dobru ocjenu.

What is the difference between kad and kada? Could I say kada brat ima dobru ocjenu instead?

Kad and kada both mean when.

kad – shorter, very common in everyday speech and neutral writing
kada – a bit more formal or emphatic, but also very common and fully correct

In this sentence, you can use either:

Roditelji su ponosni kad brat ima dobru ocjenu.
Roditelji su ponosni kada brat ima dobru ocjenu.

There’s no change in meaning. It’s mostly a stylistic choice.

Can I put the kad-clause at the beginning, like Kad brat ima dobru ocjenu, roditelji su ponosni?

Yes, that word order is completely natural:

Kad brat ima dobru ocjenu, roditelji su ponosni.
= When brother has a good grade, the parents are proud.

The grammar and meaning are the same. Only the emphasis changes a bit:

Roditelji su ponosni kad brat ima dobru ocjenu. → focuses slightly more on the parents’ reaction.
Kad brat ima dobru ocjenu, roditelji su ponosni. → focuses slightly more on the time/condition (when this happens).

Notice the comma:

Subordinate clause first → comma after it:
Kad brat ima dobru ocjenu, roditelji su ponosni.
Main clause first → normally no comma:
Roditelji su ponosni kad brat ima dobru ocjenu.

In English we say “proud of” someone. Why is there no na here, like ponosni na brata?

Croatian uses ponosan in two main patterns:

Proud of a person/thing (noun) → ponosan na + accusative
- Roditelji su ponosni na brata. – The parents are proud of (their) brother.
- Ponosan sam na tebe. – I am proud of you.
Proud because of a situation (clause) → ponosan
- da/kad/što
  - clause (no na)
- Roditelji su ponosni kad brat ima dobru ocjenu.
  Here, the reason for their pride is the whole kad-clause.
- Ponosna sam što si došla. – I’m proud (that) you came.

So:

ponosni na brata – proud of the brother (noun phrase)
ponosni kad brat ima dobru ocjenu – proud when brother has a good grade (whole clause)

Both are correct, but they’re used in different structures.

Why is it ima (has) and not something like dobije (gets)? Can I say kad brat dobije dobru ocjenu instead?

You can say both, but they describe slightly different things.

ima dobru ocjenu – has a good grade
- Describes a state: the situation in which he has the good grade.
- Suggests parents are proud whenever he is in that state.
dobije dobru ocjenu – gets/receives a good grade
- dobiti is perfective, focusing on the event/moment of getting the grade.
- Suggests parents are proud each time he gets a good grade.

So:

Roditelji su ponosni kad brat ima dobru ocjenu.
Parents are proud when he has a good grade (state).
Roditelji su ponosni kad brat dobije dobru ocjenu.
Parents are proud when he gets a good grade (event).

Both are grammatical; it’s just a nuance of meaning.

Can I leave out su, like Roditelji ponosni kad brat ima dobru ocjenu?

In standard Croatian, no. You need some form of biti (to be) to link the subject and the adjective.

Correct:

Roditelji su ponosni kad brat ima dobru ocjenu. – The parents are proud when brother has a good grade.

If you say:

Roditelji ponosni kad brat ima dobru ocjenu.

it sounds like very telegraphic or broken speech, not like a normal sentence.

You might see su omitted:

in short answers:
Jesu roditelji ponosni? – Jesu. (Are the parents proud? – They are.)
in headlines or note-style writing

But in normal sentences, keep su.

In English we would say “They are proud …”. Why isn’t there any word meaning “they” in this sentence?

Croatian subject pronouns (ja, ti, on, ona, mi, vi, oni…) are often dropped, because the subject is clear from:

the verb ending, or
an explicit noun that’s already there.

In Roditelji su ponosni…:

Roditelji itself is the subject (the parents), so there is no need for oni (they).

You could say:

Oni su ponosni kad brat ima dobru ocjenu. – They are proud when brother has a good grade.

This is grammatically fine, but it normally implies some emphasis or contrast:

Učitelji su strogi, ali roditelji su ponosni. Oni su ponosni, a drugi nisu.
Teachers are strict, but the parents are proud. They are proud, and the others are not.

Without that contrast, you just say Roditelji su ponosni….

What is the difference between su and jesu? When would I say Roditelji jesu ponosni?

Both are 3rd person plural of biti (to be):

su – short, clitic form → used normally in statements:
- Roditelji su ponosni.
jesu – full, stressed form → used for emphasis or in short answers:
- Jesu roditelji ponosni? – Are the parents proud?
- Jesu. – They are.
- Roditelji jesu ponosni, ali su i zabrinuti. – The parents are proud, but they are also worried.

In your sentence, the neutral form is Roditelji su ponosni…. Using jesu in the middle makes it sound contrastive: “They are proud (even if someone thinks otherwise)”.

How do you pronounce ocjenu? The letters c and j together look confusing.

Ocjenu is pronounced approximately like:

[o‑tsyé‑nu]

Details:

o – like o in not (but a bit shorter/cleaner)
c – always like ts in cats
cj – comes out like “tsy”
e – like e in bet
u – like oo in book (short)

So you can think of ocjenu as “OTSYE-nu”, with the stress on the first syllable: OC‑je‑nu.