Kad je moj brat pao niz stepenice, odmah smo zvali hitnu.

Kad means when in this sentence.

It introduces a time clause:

• Kad je moj brat pao niz stepenice = When my brother fell down the stairs

In everyday Croatian, kad is very common. You may also see kada, which is a slightly fuller form. In most situations, they mean the same thing.

Je is the 3rd person singular form of the auxiliary verb biti (to be) used to form the past tense.

Croatian past tense is usually made with:

• a form of biti
  • a past participle

So:

• je pao = fell / literally has fallen

As for position, je is a clitic, and clitics in Croatian usually come very early in the clause, often in the second position. That is why you get:

• Kad je moj brat pao...

rather than something more English-like.

Pao is the past participle of pasti (to fall).

It agrees with the subject:

• pao = masculine singular
• pala = feminine singular
• palo = neuter singular
• pali = masculine personal plural / mixed plural in some contexts
• pale = feminine plural

Since moj brat means my brother, which is masculine singular, the correct form is pao.

For example:

• Moj brat je pao. = My brother fell.
• Moja sestra je pala. = My sister fell.

Moj brat is in the nominative, because it is the subject of the sentence.

• moj = my
• brat = brother

So:

• moj brat = my brother

In Croatian, the subject of the sentence is typically in the nominative case.

Niz stepenice means down the stairs.

Here:

• niz is a preposition meaning down
• stepenice means stairs

So:

• pasti niz stepenice = to fall down the stairs

This is a very common expression.

After niz, Croatian normally uses the accusative when there is motion down along something.

So in:

• pao niz stepenice

the noun is in the accusative.

A useful thing to know is that stepenice is a plural noun, and its nominative plural and accusative plural look the same:

• nominative: stepenice
• accusative: stepenice

So you cannot see the case from the form alone here, but grammatically it is accusative because of niz and the motion meaning.

No. A learner may also encounter stube or stepenište, depending on region and meaning.

Very roughly:

• stepenice = stairs / steps
• stube = also stairs, common in some varieties
• stepenište = staircase / stairwell

In this sentence, stepenice is completely natural.

Odmah means immediately, right away, or at once.

So:

• odmah smo zvali hitnu = we immediately called the ambulance

It adds the idea that the action happened without delay.

Smo is also a clitic, like je, so it tends to come near the beginning of its clause, usually in second position.

That is why Croatian naturally says:

• odmah smo zvali hitnu

Here the first element of the clause is odmah, so the clitic smo comes right after it.

This clitic placement is one of the things that often feels unusual to English speakers.

Zvali is the past participle of zvati, meaning to call.

With smo (we are / we have, as an auxiliary here), it forms the past tense:

• smo zvali = we called

The subject we is not stated separately because Croatian often leaves subject pronouns out when the verb form already makes the meaning clear.

Because the auxiliary smo means we, and the participle must agree with the subject in number and, in the plural, also partly by gender rules.

Here the implied subject is mi (we), so the plural form zvali is used.

You could think of it as:

• (Mi) smo zvali hitnu. = We called the ambulance.

The pronoun mi is omitted because it is not necessary.

This is a very common learner question.

Hitnu is the accusative singular feminine form, because it is the direct object of zvali (called).

The full expression is:

• hitna pomoć = emergency medical service / ambulance

In everyday speech, Croatians very often shorten this and just say:

• hitna in the nominative
• hitnu in the accusative

So:

• Zvali smo hitnu. = We called the ambulance / emergency services.

Even though only the adjective appears on the surface, it stands for the full phrase.

It can mean either the ambulance or the emergency medical service, depending on context.

In this sentence, English might translate it as:

• we called the ambulance
• we called emergency services

Both are reasonable. In Croatian everyday usage, zvati hitnu is the normal expression.

The comma separates the subordinate time clause from the main clause.

• Kad je moj brat pao niz stepenice, = subordinate clause
• odmah smo zvali hitnu. = main clause

This is standard punctuation in Croatian, just as in English you would often write:

• When my brother fell down the stairs, we immediately called the ambulance.

Yes, Croatian word order is flexible, but not completely free.

For example, you could also say:

• Odmah smo zvali hitnu kad je moj brat pao niz stepenice.

This changes the emphasis a little but keeps the basic meaning.

However, clitics like je and smo still need to follow Croatian clitic-placement rules, so not every rearrangement sounds natural.

In Croatian, zvati hitnu is the normal idiomatic expression for to call an ambulance / emergency services.

Even though the event is a single completed action, Croatian often uses zvati in this kind of context very naturally.

You may also hear perfective verbs such as pozvati or nazvati in some contexts, but:

• zvati hitnu is extremely common and idiomatic
• learners should definitely recognize it as the standard everyday phrase

Yes. Both clauses are in the Croatian past tense.

• je pao = fell
• smo zvali = we called

Croatian past tense is built with:

• auxiliary biti
• past participle

So the sentence contains two past-tense verb phrases:

• je pao
• smo zvali

Because Croatian often drops subject pronouns when the verb already shows who the subject is.

• smo already tells you the subject is we
• so mi is unnecessary unless you want emphasis

Compare:

• (Mi) smo zvali hitnu.

Both are grammatical, but without mi is more neutral and natural here.

Yes, it sounds natural and normal.

A native speaker would easily say:

• Kad je moj brat pao niz stepenice, odmah smo zvali hitnu.

The especially everyday part is zvati hitnu, which is a very common real-life expression.