Learn Hardcore Croatian: Djeca se radije igraju u parku nego gledaju televiziju. - Children prefer to play in the park rather than watch television.

Djeca se igraju. = Children are playing (for fun).
If you say Djeca igraju, it sounds like They are playing something specific (a game, a sport):
Djeca igraju nogomet. = The children are playing football.

So here, you should not leave se out. Igrati se is the normal way to say that children are just “playing” in general.

Why is it igrati se (with se) for children playing, but sometimes I see igrati without se?

Croatian uses:

igrati se = to play (intransitive, no stated game, like kids playing)
- Djeca se igraju u parku. = The children are playing in the park.
igrati
- object = to play something (a game, sport, role, match)
  - Igram nogomet. = I play football.
  - Igraju šah. = They play chess.
  - Igra glavnu ulogu. = He/She plays the main role.

In your sentence, there is no specific game mentioned, so igrati se is used.

Why is the verb igraju (3rd person plural) if djeca ends in -a and looks singular?

Djeca is a bit special:

It looks singular (ends in -a), but grammatically it is plural (neuter plural).
That is why the verb is 3rd person plural: djeca se igraju.

Compare:

dijete se igra = the child plays (singular)
djeca se igraju = the children play (plural)

So: djeca igraju, djeca gledaju, djeca jedu, etc.

What exactly is radije here, and how is it different from više?

Radije is the comparative form of rado (gladly, willingly).
It means rather / preferably / would rather and is used to express preference between activities:

Djeca se radije igraju u parku nego gledaju televiziju.
= The children would rather play in the park than watch TV.

Više means more (quantity, degree, frequency):

Djeca više vremena provode u parku. = The children spend more time in the park.
Više volim kavu nego čaj. = I like coffee more than tea.

So:

radije → preference between choices
više → more (amount, degree, frequency)

You normally say radije X nego Y.

Where can radije go in the sentence? Is Djeca radije se igraju u parku… possible?

In this sentence, se is a clitic and Croatian clitics must stand in (roughly) second position in the clause. That’s why we say:

Djeca se radije igraju u parku… ✅

Natural alternatives:

Djeca se igraju radije u parku nego kod kuće. (different emphasis)
Radije se djeca igraju u parku nego gledaju televiziju. (emphasis on radije)

But Djeca radije se igraju… ❌ is not standard, because se is pushed too far from second position.

Why is it u parku and not u park?

Croatian uses different cases after u depending on the meaning:

u
- locative = location (in, at)
  - Djeca se igraju u parku. = They are playing in the park. (no movement)
u
- accusative = direction (into)
  - Idemo u park. = We are going into the park.

In your sentence, the children are already there, just playing in the park, so you use locative: u parku.

What case is televiziju, and why that form?

Televiziju is the accusative singular form of televizija.

Reason:

It is the direct object of the verb gledaju (they watch).
In Croatian, direct objects normally take the accusative case.

Pattern:

Nominative: televizija (subject)
Accusative: televiziju (object)

So: gledaju televiziju = they watch TV.

Why is there no word for the or a before parku or televiziju?

Croatian has no articles (no direct equivalents of a/an or the).

u parku can mean in a park or in the park, depending on context.
gledaju televiziju can be watch television / watch the TV.

Definiteness (whether it is the or a) is understood from context, not from a separate word.

Why do we use nego after radije and not od?

Both nego and od can appear in comparisons, but they are used differently.

With radije, the standard pattern is:
- radije X nego Y = rather X than Y
- Djeca se radije igraju u parku nego gledaju televiziju.

General tendencies:

od is common when you compare nouns or pronouns:
- veći od brata = bigger than (his) brother
- bolji od mene = better than me
nego is common when you compare whole phrases/clauses or when the first part is already a comparative:
- Radije čitam nego gledam film. = I’d rather read than watch a film.

So here radije … nego … is the normal structure.

Should there be a comma before nego?

In this sentence, no comma is used:

Djeca se radije igraju u parku nego gledaju televiziju. ✅

Reason:

You have one subject (djeca) and two verb phrases (predicate parts) connected by nego.
In such coordinated predicates with the same subject, Croatian usually does not put a comma.

A comma is more typical when the parts are longer, more independent, or have different subjects.

Could we repeat djeca in the second part: Djeca se radije igraju u parku nego djeca gledaju televiziju?

You can repeat djeca, but it sounds heavy and unnatural in this simple sentence.

Natural:

Djeca se radije igraju u parku nego gledaju televiziju. ✅

Possible but stylistically clumsy:

Djeca se radije igraju u parku nego djeca gledaju televiziju. ⚠️

Since the subject is the same in both parts, Croatian normally omits the repeated subject.

Should it be nego se gledaju televiziju to match the se from se igraju?

No. Se belongs to the verb igrati se, not to the whole sentence.

igrati se = to play (reflexive verb)
gledati = to watch (non‑reflexive verb)
gledati se would mean to watch oneself / each other, which is wrong here.

So the contrast is correctly:

se radije igraju vs. gledaju televiziju
and not se gledaju televiziju.

Can I say Djeca radije igraju u parku nego gledaju televiziju (without se)?

You can say it, but it changes the nuance:

Djeca se radije igraju u parku…
→ general children’s play, just playing for fun.
Djeca radije igraju u parku…
→ sounds more like “They rather play (some game) in the park…”, as if a specific game is implied.

In everyday speech you will very often hear igrati se for children’s play without specifying the game, so with se is more typical and natural here.

Why is it gledaju televiziju and not gledaju televizor?

Both exist, but they mean slightly different things:

gledati televiziju
= to watch television as a medium (programs, shows, TV in general)
→ This is what you have in the sentence.
gledati televizor
= to watch the TV set (the physical device), or at least it sounds more focused on the device.

In practice, when you mean watch TV (shows, programs), you normally say gledati televiziju, as in the example sentence.