Kiedy mężczyzna zemdlał na przystanku, ktoś od razu wezwał karetkę.

That’s a very common question. Mężczyzna is a masculine noun even though it ends in -a.

Polish has a small group of masculine nouns with this pattern, especially words for male people, for example:

• mężczyzna = man
• kolega = male friend / colleague
• poeta = poet

So in this sentence, mężczyzna is still grammatically masculine, and that affects things like past-tense verbs:

• mężczyzna zemdlał = the man fainted

The verb ends in -ł, which shows masculine singular in the past tense.

Because mężczyzna is the subject of the clause, so it stays in the nominative case.

In the sentence:

• Kiedy mężczyzna zemdlał... = When the man fainted...

the man is the one doing the action, so nominative is used.

You would use mężczyznę in the accusative, for example when the man is the direct object:

• Widzę mężczyznę. = I see the man.

Kiedy means when.

Here it introduces a subordinate clause:

• Kiedy mężczyzna zemdlał na przystanku = When the man fainted at the bus stop

Then the main clause follows:

• ktoś od razu wezwał karetkę = someone immediately called an ambulance

In Polish, subordinate clauses are normally separated by a comma, so the comma here is required.

Zemdlał is:

• past tense
• 3rd person singular
• masculine
• from the verb zemdleć = to faint

So:

• zemdlał = he fainted

Because the subject is mężczyzna (a masculine noun), the masculine past form is used.

Compare:

• mężczyzna zemdlał = the man fainted
• kobieta zemdlała = the woman fainted

Na przystanku means at the bus stop / at the stop.

Here na expresses location, so it takes the locative case:

• przystanek = stop
• na przystanku = at the stop

This is different from na used with movement toward a place, which often takes the accusative.

For example:

• Jestem na przystanku. = I am at the stop.
• Idę na przystanek. = I’m going to the stop.

So in your sentence, na przystanku is locative because the action happened there.

Not always, but very often in everyday use it means a bus stop, tram stop, or just stop in public transport.

So:

• na przystanku usually means at the stop

If context makes it clear, Polish often does not specify bus or tram.

Ktoś means someone.

It is an indefinite pronoun used when the person is unknown or not identified.

So:

• ktoś wezwał karetkę = someone called an ambulance

Related words:

• kto = who
• ktoś = someone
• nikt = nobody

Od razu is a fixed expression meaning:

• immediately
• right away
• straight away

You should learn it as a whole phrase rather than trying to translate each word literally.

Examples:

• Zadzwoń od razu. = Call right away.
• Od razu mu pomogli. = They helped him immediately.

In your sentence, it shows a quick reaction:

• ktoś od razu wezwał karetkę = someone immediately called an ambulance

Because in Polish you summon/call for an ambulance, rather than phone the ambulance directly.

The verb wezwać means:

• to call
• to summon
• to send for

So:

• wezwać karetkę = to call an ambulance

By contrast, zadzwonić means to phone / to make a phone call, and it is used differently:

• zadzwonić po karetkę = to call for an ambulance
• zadzwonić na pogotowie = to call the emergency medical service

So wezwał karetkę is a very natural and standard way to say it.

Because karetkę is the accusative singular form of karetka.

The ambulance is the direct object of wezwał:

• wezwał co? → karetkę

So:

• karetka = nominative
• karetkę = accusative

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

• mam książkę from książka
• widzę kobietę from kobieta
• wezwał karetkę from karetka

Yes. Wezwał is the past tense of the perfective verb wezwać.

Polish often uses perfective verbs when talking about a completed one-time action. Here, the person performed a single completed action:

• they called an ambulance

That is why perfective fits well.

Compare the general idea:

• wzywać = to be calling / to call repeatedly / habitually
• wezwać = to call once, successfully, as a completed act

In this sentence, the completed event is what matters.

Yes, Polish word order is more flexible than English, although not completely free.

The sentence:

• Kiedy mężczyzna zemdlał na przystanku, ktoś od razu wezwał karetkę.

is very natural.

You could also hear variations like:

• Kiedy mężczyzna zemdlał na przystanku, od razu ktoś wezwał karetkę.
• Karetkę od razu wezwał ktoś, kiedy mężczyzna zemdlał na przystanku.

But these alternatives may sound more marked or place emphasis in different places. The original version is the most neutral and natural for a learner to use.

A rough pronunciation guide is:

• Kiedy ≈ KYEN-dih
• mężczyzna ≈ men-CHIH-zna
• zemdlał ≈ ZEM-dwaw or ZEM-dlahw depending on how narrowly you describe it
• na przystanku ≈ na psheh-STAN-koo
• ktoś ≈ ktosh
• od razu ≈ od RA-zoo
• wezwał ≈ VEZ-vaw
• karetkę ≈ ka-RET-ken

A few useful notes:

• rz is usually pronounced like the s in measure
• sz is like sh, but harder and more retroflex
• ę at the end of a word is often not pronounced as a full nasal vowel in normal speech
• consonant clusters like mdł in zemdlał can be tricky, so learners often need practice saying them slowly first

Yes, absolutely. That is a very natural English translation.

A few good equivalents are:

• When the man fainted at the bus stop, someone immediately called an ambulance.
• When the man passed out at the stop, someone called an ambulance right away.

The exact English wording can vary, but the Polish sentence stays the same.