Learn Hardcore Croatian: Djeca cijelo vrijeme trče u parku. - The children run in the park all the time.

Croatian doesn’t distinguish “run” vs. “are running” with different forms; context and aspect (imperfective vs. perfective) give that nuance. Here, cijelo vrijeme helps show it’s ongoing / continuous.

What does cijelo vrijeme mean, and how is it different from words like stalno?

Cijelo vrijeme literally means the whole time.
In this sentence it is translated as all the time / the whole time.

Nuances:

cijelo vrijeme – emphasizes the entire duration of a specific period:
- While we were there, the children ran the whole time.
stalno – means constantly, all the time in general, often with a slightly negative or exaggerated tone:
- Djeca stalno trče u parku. = The children are always running in the park (they do this a lot / habitually).

So cijelo vrijeme focuses on one stretch of time, while stalno is more about repeated / habitual behavior.

Why is it cijelo vrijeme and not cijeli vrijeme or cijela vrijeme?

Cijelo is an adjective meaning whole / entire, and it must agree with the noun vrijeme in:

Gender: vrijeme is neuter
Number: singular
Case: accusative here (it behaves like a time expression)

So we need the neuter singular accusative form: cijelo vrijeme.

If the noun were masculine:

cijeli dan – the whole day

Feminine:

cijela noć – the whole night

Neuter:

cijelo vrijeme – the whole time

Why is it u parku and not u park? What case is parku?

The phrase u parku uses the locative case after the preposition u to express location (where?).

u
- locative = in / at (static location, no movement)

Park in the singular:

Nominative: park
Genitive: parka
Dative: parku
Accusative: park
Vocative: parke
Locative: parku
Instrumental: parkom

So:

u parku = in the park (location)

If you expressed movement into the park, you would use u + accusative:

Idem u park. = I’m going into the park.

Could you also say na parku, and what would be the difference from u parku?

In this context, u parku is the normal, natural choice:

u parku = in the park, inside the park area

Na parku would be unusual and usually wrong here. Na is often used for:

Surfaces: na stolu – on the table
Open areas / fields / squares: na trgu – on the square
Some institutions / events: na fakultetu – at university, na koncertu – at the concert

A park is normally conceptualized as a 3D area you are inside, so Croatian uses u parku, not na parku.

Why doesn’t the sentence use any articles like “the” or “a”, as in “the children” or “the park”?

Croatian does not have articles (no equivalents of a/an or the).

Whether you understand it as the children or children depends entirely on context, not on a word in the sentence.

So Djeca cijelo vrijeme trče u parku can be:

The children run in the park all the time.
or
Children run in the park all the time.

The language simply doesn’t mark this difference grammatically.

Can the word order be changed, for example to Djeca trče u parku cijelo vrijeme or Cijelo vrijeme djeca trče u parku?

Yes. Croatian word order is relatively flexible, and all of these are possible:

Djeca cijelo vrijeme trče u parku.
Djeca trče u parku cijelo vrijeme.
Cijelo vrijeme djeca trče u parku.
U parku djeca cijelo vrijeme trče.

The basic meaning stays the same, but the focus shifts slightly:

Putting cijelo vrijeme first (Cijelo vrijeme djeca…) emphasizes the duration.
Putting u parku first (U parku djeca…) emphasizes the location.

The version you gave is a very natural neutral order.

Can you drop the subject djeca and just say Cijelo vrijeme trče u parku?

Yes, you can omit the subject in Croatian when it is clear from context. Croatian is a pro‑drop language.

Cijelo vrijeme trče u parku. = They are running in the park the whole time.

The verb ending -e in trče already tells us it’s they (third person plural). You only need djeca if you want to specify who “they” are, or if it’s not clear from context.

How do you pronounce djeca, cijelo, and trče?

Approximate pronunciation (IPA):

djeca – /ˈd͡ʑet͡sa/
- dj like the “j” in jeans, but palatal; c like ts in cats
cijelo – /ˈt͡sijelo/
- ci like tsi, je like ye in yes
trče – /ˈtrt͡ʃe/
- č like ch in church, but harder/shorter

Stress is on the first syllable: DJEc‑a, CI‑je‑lo, TR‑če.

Is there a difference between trče and trčaju? I’ve seen both.

The standard present tense form in Croatian is trče for oni/one/ona (“they”).

oni trče – they run

Trčaju is heard in some dialects and colloquial speech, but it is considered non‑standard in Croatian. In standard language (what you’d use in writing, exams, official settings), use trče.

How would you say this sentence in the past and in the future?

Present (original):

Djeca cijelo vrijeme trče u parku.
- The children are running / run the whole time in the park.

Past (perfect):

Djeca su cijelo vrijeme trčala u parku.

Notes:

Auxiliary: su = they have / they did
Past participle: trčala – neuter plural to agree with djeca (neuter plural)

In everyday speech, many people also say trčali (masculine plural) with djeca, but trčala is grammatically more precise.

Future (future I):

Djeca će cijelo vrijeme trčati u parku.
- The children will run / will be running in the park the whole time.

Here trčati is the infinitive, and će is the future auxiliary.