Learn Hardcore Croatian: Za rođendan slavimo u parku s obitelji. - For a birthday we celebrate in the park with the family.

za rođendan (literally “for (the) birthday”) with za + accusative:
- Often expresses occasion or purpose.
- Very common in phrases like:
  - Za rođendan slavimo u parku. – For (someone’s) birthday we celebrate in the park.
  - Što želiš za rođendan? – What do you want for your birthday?
na rođendan (literally “on (the) birthday”) with na + accusative/locative:
- Often means “on the day of the birthday” or “(at) the birthday party”.
- E.g. Na rođendan sam uvijek s prijateljima. – On my birthday I am always with friends.

In your sentence, za rođendan focuses on the occasion (“for the birthday [occasion] we celebrate in the park”), which is very natural here.

What case is rođendan in, and why doesn’t its form change?

In za rođendan, the noun rođendan is in the accusative case, because the preposition za always takes the accusative.

For masculine, inanimate nouns like rođendan, the nominative and accusative look the same:

Nominative: rođendan – Birthday (subject form)
Accusative: rođendan – Birthday (object/after za)

So even though the case changes (nominative → accusative), the form doesn’t change, which is why you don’t see any ending difference here.

Why is there no word for “we” in the sentence? Where is the subject?

The subject “we” is contained in the verb form slavimo.

Croatian is a pro‑drop language: subject pronouns (ja, ti, on, mi, vi, oni) are usually dropped, because the verb ending shows who is doing the action.

slavim – I celebrate
slaviš – you (sg) celebrate
slavi – he/she/it celebrates
slavimo – we celebrate
slavite – you (pl) celebrate
slave – they celebrate

So slavimo already tells you “we celebrate”, and adding mi is usually only for emphasis:

Mi slavimo u parku. – We (as opposed to someone else) celebrate in the park.

Why is slavimo in the present tense if the meaning is about a future plan?

In Croatian (as in English), the present tense can be used to talk about:

something happening now, or
a planned or arranged future event, when the context makes that clear.

So:

Za rođendan slavimo u parku.
can mean:
- “For (the) birthday, we are celebrating in the park” (plan for the future), or
- “For (the) birthday, we celebrate in the park” (a general habit or tradition).

If you want to be very clearly future, you can say:

Za rođendan ćemo slaviti u parku. – We will celebrate in the park for (the) birthday.

But the simple present slavimo is perfectly normal for talking about a planned event.

Where is the word “it” (as in “we celebrate it”) in the Croatian sentence?

Croatian often omits objects when they are obvious from context.

English:

“For (his) birthday, we celebrate it in the park with the family.”

Croatian:

Za rođendan slavimo u parku s obitelji.

The direct object (“his birthday”, “it”) is understood from za rođendan and from the whole context, so Croatian doesn’t need to repeat it with a pronoun. You could add it, but that would usually sound awkward or too heavy:

❌ Za rođendan ga slavimo u parku. – Grammatically possible, but stylistically odd here.

Normally, you simply leave it out.

Why is it u parku and not u park?

The preposition u can take either accusative or locative, depending on the meaning:

u + accusative = movement into something
- Idemo u park. – We’re going to (into) the park.
u + locative = location in something
- Sjedimo u parku. – We’re in the park.

In Za rođendan slavimo u parku, you are not describing movement into the park, but the place where you celebrate: in the park. So you use the locative case:

park → u parku (locative singular)

Why is it s obitelji and not something like sa obitelji or s obiteljom?

There are two things here: the preposition form (s/sa) and the noun case (obitelji).

s vs sa
Both mean “with”, but sa is mainly used:
- before words starting with s, z, š, ž (e.g. sa sestrom, sa psom)
- or sometimes to avoid awkward consonant clusters.
Since obitelji starts with o, the basic, shorter form s is used:
- s obitelji – with (the) family
Why obitelji and not obitelj or obiteljom?
The preposition s (“with”) takes the instrumental case.
For obitelj (feminine noun), the instrumental singular is obitelji:
- Nominative: obitelj – family
- Instrumental: (s) obitelji – with (the) family
So s obitelji literally means “with (the) family”, and the form obitelji here is the instrumental case, not plural.

Is obitelji singular or plural here?

In this sentence, obitelji is singular, instrumental case.

The noun obitelj (family) has many cases that look like obitelji:

Genitive singular: obitelji – of the family
Dative singular: obitelji – to/for the family
Locative singular: u obitelji – in the family
Instrumental singular: s obitelji – with the family
Nominative plural: obitelji – families

So the form is the same for several cases and also for plural, but in s obitelji we know it’s instrumental singular from the preposition s and the meaning “with (the) family”.

Why are there no words for “the” or “our” in the sentence?

Croatian has no articles like “a” or “the”, so:

rođendan can mean “a birthday” or “the birthday”, depending on context.
obitelj / obitelji can mean “(the) family”.

Possessives like “my/our/their” are only added when needed:

s obitelji – with (the) family / with our family (if context is clear)
s našom obitelji – with our family (explicitly)
s tvojom obitelji – with your family

In your sentence, it’s natural to assume it means “our family” or “his/her family” from context, so Croatian just says s obitelji.

Can the word order be different, like Rođendan slavimo u parku s obitelji?

Yes. Croatian has relatively flexible word order, and several versions are possible, with slightly different emphasis:

Za rođendan slavimo u parku s obitelji.
– Puts focus on the occasion (“For the birthday, we celebrate in the park with (the) family.”)
Rođendan slavimo u parku s obitelji.
– Emphasises the birthday as the thing being celebrated.
Slavimo rođendan u parku s obitelji.
– More neutral; very close to English “We celebrate (the) birthday in the park with (the) family.”

All are grammatically fine. The choice mostly depends on what you want to highlight in the sentence.