Learn Hardcore Croatian: Djeca se igraju na tepihu, jer je pod hladan. - The children are playing on the carpet because the floor is cold.

igrati se = to play (in general, to play around, to be engaged in play)
- Djeca se igraju. = The children are playing.
igrati (without se) = to play something specific (a game, a sport, an instrument, a role)
- Djeca igraju nogomet. = The children play football.
- On igra gitaru. = He plays the guitar.

In Djeca se igraju, you cannot leave se out.
If you said Djeca igraju, listeners would expect you to say what they are playing: Djeca igraju nogomet/kartu/igru…

Why is the verb igraju plural when djeca doesn’t look like a normal plural noun?

Djeca means children. It is grammatically neuter plural, even though it doesn’t end in the usual plural endings like -i, -e, or -ovi.

Because djeca is plural, the verb must be in the 3rd person plural:

Djeca se igraju. – The children are playing.
Dijete se igra. – The child is playing. (dijete = child, singular)

So, always use plural verbs with djeca:

Djeca se igraju.
Djeca su umorna. – The children are tired.

Why is it na tepihu and not na tepih?

In Croatian, the preposition na can take either:

Locative → when something is on/in a place (no movement), or
Accusative → when there is movement to a place.

Here, the children are already on the carpet (no movement to it), so you use locative:

na tepihu (locative) = on the carpet
- Djeca se igraju na tepihu. – The children are playing on the carpet.

If there were movement onto the carpet, you would use accusative:

na tepih (accusative) = onto the carpet
- Djeca idu na tepih. – The children are going onto the carpet.

What case is tepihu and how is it formed?

Tepihu is in the locative singular case.

Nominative (dictionary form): tepih – carpet
Locative singular: (na) tepihu – on the carpet

For many masculine nouns ending in a consonant, the locative singular adds -u:

tepih → (na) tepihu – on the carpet
stol → (na) stolu – on the table
pod → (na) podu – on the floor

In this sentence, na tepihu literally means on (the) carpet.

Why is there a comma before jer?

Jer is a subordinating conjunction meaning because. It introduces a reason clause.

In Croatian, you normally put a comma before such conjunctions:

Djeca se igraju na tepihu, jer je pod hladan.
= The children are playing on the carpet, because the floor is cold.

Other conjunctions that usually take a comma before them: da, ako, iako, kada, dok, zato što, etc.

So, the comma is there because jer starts a subordinate clause explaining the reason.

Why is the word order jer je pod hladan and not jer pod je hladan or jer je hladan pod?

The key point is the tiny verb je (is). Je is a clitic – a short unstressed word that must stand in the second position in its clause.

In the clause:

jer je pod hladan
- jer = first word of the clause
- je = clitic, so it comes right after jer

If you change the order, you must still respect the “second position” rule. For example:

Pod je hladan. – normal statement (here pod is first, je second)
In a jer clause, jer is first, so je must come second: jer je pod hladan.

You could reorder the rest for emphasis:

jer je hladan pod – grammatically possible, but unusual and marked; jer je pod hladan is the neutral, natural order.

Why is it hladan and not hladno or hladna?

Hladan is an adjective meaning cold. After the verb biti (to be), the adjective must agree with the subject in gender, number, and case.

The subject is pod (floor):

pod = masculine, singular, nominative

So the adjective must be masculine singular nominative:

pod je hladan – the floor is cold

Other possibilities with different nouns:

soba je hladna – the room is cold (soba = feminine)
mlijeko je hladno – the milk is cold (mlijeko = neuter)

Hladno can also be an adverb (it is cold in general: Hladno je.), but here we are describing a masculine noun pod, so hladan is required.

What exactly does pod mean? Is it the same as “floor”?

Yes, pod in this context means floor, the surface you walk on inside a room.

pod – floor
- Pod je hladan. – The floor is cold.
- Na podu je tepih. – There is a carpet on the floor.

Other related words (for context):

kat – floor/storey of a building (1st floor, 2nd floor, etc.)
tlo – ground/soil (more general, often outside)

In jer je pod hladan, pod is simply the floor.

Could we say Djeca se igraju na podu instead of na tepihu? What is the difference?

Yes, you can say:

Djeca se igraju na podu. – The children are playing on the floor.

The difference is:

na tepihu – on the carpet
na podu – on the floor (directly on the floor surface)

In the original sentence, they are on the carpet, and the reason given is that the floor (pod) is cold. So the contrast is:

location: na tepihu (on the carpet)
reason: pod je hladan (the floor is cold)

Is jer always translated as “because”? Can you start a sentence with Jer like in English?

Jer usually means because and introduces a reason clause:

Ne izlazim, jer pada kiša. – I’m not going out because it’s raining.

You can start a sentence with Jer if it continues a previous idea, just like in English:

Zašto se djeca igraju na tepihu?
– Jer je pod hladan.
(Why are the children playing on the carpet? – Because the floor is cold.)

However, in formal writing, you more often use complete sentences (with the main clause plus the jer-clause) rather than a sentence starting with Jer alone.

Does Djeca se igraju mean “the children play” or “the children are playing”? How do you say the continuous tense in Croatian?

Croatian does not have a special continuous tense like English (am/is/are playing). The present tense covers both:

Djeca se igraju.
- can mean The children play (habitually)
- or The children are playing (right now)

The meaning is usually clear from context. If you really need to stress “right now”, you can add an adverb:

Djeca se sada igraju. – The children are playing now.
Djeca se uvijek igraju na tepihu. – The children always play on the carpet.