Learn Hardcore Croatian: On jede sendvič i gleda na ekran mobitela dok čeka vlak. - He eats a sandwich and looks at the screen of his phone while he waits for the train.

On jede sendvič… = He is eating a sandwich…
You can also say simply Jede sendvič…, and it is still understood as he (or she, from context).

You keep On when:

you are introducing the person for the first time,
you want to contrast (On jede, ona ne jede – He is eating, she is not),
or you want extra emphasis on he.

In many neutral contexts, native speakers would actually prefer Jede sendvič i gleda na ekran mobitela dok čeka vlak.

Why is jede used instead of something like is eating? Does Croatian have a separate present continuous tense?

Croatian does not have a separate present continuous form like English.

The simple present (jede) covers both:

He eats a sandwich (in general).
He is eating a sandwich (right now).

Context decides which meaning is intended. Here, because the actions are accompanied by dok čeka vlak (while he is waiting for the train), the natural reading is ongoing: He is eating… and looking… while he is waiting….

To make it very clearly “right now”, you could add time words:

Sad jede sendvič. – He is eating a sandwich now.
Upravo jede sendvič. – He is eating a sandwich right this moment.

Why does sendvič appear without any article like a or the?

Croatian does not use articles (no a / an / the).

Definiteness and indefiniteness are understood from context, not marked by a separate word. So:

On jede sendvič. can mean:
- He is eating a sandwich.
- He is eating the sandwich.

Grammatically, sendvič here is:

masculine, singular,
accusative case (direct object of jede),
same form as nominative (for inanimate masculine nouns, nominative = accusative in singular).

Which English article you choose in translation depends only on the broader context, not on anything visible in the Croatian form.

What exactly is going on in ekran mobitela, and why does mobitela end in -a?

Ekran mobitela is a noun + noun possessive structure:

ekran – screen (nominative singular)
mobitela – of the mobile phone (genitive singular of mobitel)

So ekran mobitela literally = the screen of the mobile phone / the phone’s screen.

The ending -a here marks genitive singular of a masculine noun:

mobitel (nom.) → mobitela (gen.)
same pattern: auto → auta, vlak → vlaka.

In English you would use either:

a possessive noun: the phone’s screen, or
of: the screen of the phone.

Is gleda na ekran mobitela the only correct way to say he is looking at the phone screen? What about gleda u ekran?

Several variants are possible, with slightly different preferences and nuances:

Gleda na ekran mobitela.
- Literally: he is looking onto the screen of the phone.
- Understandable and used, but for many speakers, na ekran sounds a bit more like “to the screen” (direction / surface).
Gleda u ekran mobitela.
- Literally: he is looking into the screen of the phone.
- Very common for “looking at a screen” in the sense of staring into a luminous surface (phone, TV, computer).
Gleda ekran mobitela.
- No preposition: just “he is looking (at) the phone screen”.
- Also used and perfectly correct; English needs at, Croatian does not.

In everyday speech, gleda u mobitel or gleda u ekran mobitela would probably be the most typical way to express “looking at the phone screen.”

Why does čekati not use a preposition like za? In English we say wait for the train, but Croatian says čeka vlak.

In Croatian, čekati normally takes a direct object in the accusative, with no preposition:

čekati vlak – to wait for the train
čekati autobus – to wait for the bus
čekati prijatelja – to wait for a friend

So:

English: wait for the train
Croatian: čekati vlak (literally “wait the train”).

You sometimes see or hear čekati na + accusative or locative (for example čekati na vlak), but in standard Croatian čekati without a preposition is the default and most neutral form in this meaning.

How does dok work in this sentence? Does it always take the present tense?

Dok is a subordinating conjunction meaning while, as long as, or sometimes whereas. It introduces a clause with a verb:

dok čeka vlak – while he is waiting for the train

In the sentence:

main clause: On jede sendvič i gleda na ekran mobitela
subordinate clause: dok čeka vlak

Tense of the verb after dok depends on the time relationship you want to express:

Dok čeka vlak, jede sendvič. – While he is waiting (now), he is eating.
Dok je čekao vlak, jeo je sendvič. – While he was waiting for the train, he was eating a sandwich.
Dok bude čekao vlak, čitat će novine. – While he is waiting for the train (in the future), he will read the newspaper.

So dok itself does not force the present tense; it simply links the time spans of two actions.

Can the word order be changed, for example putting dok čeka vlak at the beginning, or moving sendvič?

Yes, Croatian word order is relatively flexible, and you can reorder parts for emphasis or style, as long as you respect grammar (cases, verb agreement, etc.).

Some acceptable alternatives:

Dok čeka vlak, on jede sendvič i gleda na ekran mobitela.
– While he is waiting for the train, he is eating a sandwich and looking at the phone screen.
(Initial dok‑clause sets the scene.)
On jede sendvič dok čeka vlak i gleda na ekran mobitela.
– Grammatically OK, but now dok čeka vlak can sound like it applies mainly to jede sendvič, with gleda… trailing after; context usually makes it clear.
On sendvič jede i gleda na ekran mobitela dok čeka vlak.
– Possible, but now sendvič is fronted and somewhat emphasized (what he is eating).

Meaning is mostly preserved; the main difference between such variants is which part you highlight (time frame vs. actions vs. objects). The original order is neutral and very natural.

Why are all the verbs in the imperfective aspect (jede, gleda, čeka) instead of perfective forms?

Croatian verbs come in aspect pairs: imperfective (ongoing, repeated, or unbounded) and perfective (completed, one‑time, with a clear end point).

Here we are describing simultaneous ongoing actions, so imperfective is appropriate:

jede – he is eating (process, not completed)
gleda – he is looking (ongoing activity)
čeka – he is waiting (state / process)

Perfective counterparts would suggest finished or single, whole events:

pojesti sendvič – to eat up / finish the sandwich
pogledati na ekran – to take a look at the screen (one complete look)
pričekati vlak – to wait (until the train comes, completed act of waiting)

Using perfective forms in this context would change the meaning to something like “he finishes the sandwich and takes a look at the screen while he waits,” which is not what the Croatian sentence is saying.

Could we shorten or simplify the sentence, for example to Jede sendvič i gleda u mobitel? Would that still sound natural?

Yes, several elements can be omitted or simplified and the sentence will still be natural, though slightly less precise:

(On) jede sendvič i gleda u mobitel.
– Dropping On is fine; the verb ending shows the subject.
– Replacing ekran mobitela with mobitel is colloquial and very common: people often say “look at the phone” instead of explicitly “at the phone’s screen”.

What you lose by shortening:

dok čeka vlak is removed, so you no longer know he is at the station waiting.
ekran is removed, so it is less precise (but still fully natural in everyday speech).

So:

On jede sendvič i gleda na ekran mobitela dok čeka vlak. – fuller, more descriptive.
Jede sendvič i gleda u mobitel. – shorter, more casual, but still very idiomatic Croatian.