Learn Hardcore Croatian: Kad živimo u inozemstvu, iskustvo jezika i kulture je drukčije. - When we live abroad, the experience of the language and culture is different.

živimo = we live (1st person plural)
- ja živim – I live
- ti živiš – you (sg) live
- on/ona/ono živi – he/she/it lives
- mi živimo – we live
- vi živite – you (pl) live
- oni/one/ona žive – they live

So Kad živimo u inozemstvu already means When we live abroad.
You could add mi (Kad mi živimo u inozemstvu), but then you are stressing we (as opposed to someone else), not just stating it neutrally.

Why is it u inozemstvu and not u inozemstvo?

Because Croatian uses different cases with u depending on meaning:

u + accusative = into, movement to somewhere
- Idemo u inozemstvo. = We are going abroad (into a foreign country).
u + locative = in, location where something happens
- Živimo u inozemstvu. = We live abroad (we are located there).

In your sentence:

Kad živimo u inozemstvu = When we live abroad → it’s about location, so locative is used: inozemstvu, not inozemstvo.

What case is inozemstvu, and how can I recognize it?

inozemstvu is locative singular of inozemstvo (abroad, foreign country).

Neuter noun pattern (simplified):

Nominative: inozemstvo (what? – as dictionary form)
Genitive: inozemstva (of abroad)
Dative/Locative: inozemstvu (to / in abroad)
Instrumental: inozemstvom (with / by abroad)
Accusative: inozemstvo (same as nominative for neuter)

You almost always see the locative with prepositions like u (in) or na (on, at) when they answer “where?”:

u gradu – in the city
u školi – in the school
u inozemstvu – abroad

Why is it iskustvo jezika i kulture? What case are jezika and kulture, and why?

jezika and kulture are both genitive singular:

jezik → jezika (of the language)
kultura → kulture (of the culture)

Croatian often uses the genitive to express “X of Y”, just like English experience *of something*:

iskustvo jezika i kulture
= experience of language and culture

This is the same pattern as:

šalica čaja – a cup of tea
strah rata – fear of war
promjena vremena – change of weather

So iskustvo jezika i kulture literally is experience of (the) language and (the) culture → the experience of language and culture.

Why is the verb je singular and not plural? Shouldn’t it be jesu because of “language and culture”?

The subject of the sentence is iskustvo (experience), which is singular, not jezika i kulture.

Structure:

iskustvo jezika i kulture = one noun phrase, meaning the experience (of language and culture)
je = is (3rd person singular)
drukčije = different

So:

Iskustvo jezika i kulture je drukčije.
= The experience of language and culture is different.

You would only use jesu (are) if the subject itself was plural, e.g.:

Jezik i kultura su drukčiji.
Language and culture are different.

Why is it drukčije and not drukčiji or drukčija?

Because the adjective has to agree with the gender and number of the noun iskustvo:

iskustvo is neuter singular
the adjective “different” in neuter singular is drukčije

Basic forms of the adjective:

masculine: drukčiji
feminine: drukčija
neuter: drukčije

Examples:

drugačiji jezik – a different (masc.) language
drugačija kultura – a different (fem.) culture
drukčije iskustvo – a different (neut.) experience

So in your sentence, iskustvo … je drukčije is correct agreement.

Is drukčije here an adjective or an adverb? Could I also say drugačije?

In this sentence it behaves as a predicative adjective agreeing with iskustvo (neuter singular): the experience is different → iskustvo je drukčije.

However, forms like drukčije / drugačije are also very commonly used adverbially in Croatian (differently). Context decides the interpretation.

You can definitely say:

drukčije or drugačije – they are near-synonyms.
drugačije is slightly more common in everyday speech; drukčije is fully standard and also frequent.

So another perfectly natural version is:

Kad živimo u inozemstvu, iskustvo jezika i kulture je drugačije.

Can I move je to another place in the sentence, like in English “the experience is different”?

You can move the other words, but je is a clitic and normally stays in the second position of its clause.

Correct options include:

Iskustvo jezika i kulture je drukčije. (neutral word order)
Drukčije je iskustvo jezika i kulture. (emphasis on “different”)

But you normally do not split the noun phrase like:

✗ Iskustvo je jezika i kulture drukčije. (sounds wrong/unnatural)

Rule of thumb: treat iskustvo jezika i kulture as one block, and keep je as the second element of the clause, not stuck inside that block at a random place.

Why is there a comma after u inozemstvu? Is it always needed with kad-clauses?

Yes, in standard Croatian you put a comma between a subordinate clause (introduced by kad/kada) and the main clause, when the subordinate clause comes first:

Kad živimo u inozemstvu, iskustvo jezika i kulture je drukčije.

If you reverse the order, you normally don’t use a comma:

Iskustvo jezika i kulture je drukčije kad živimo u inozemstvu.

So:

Subordinate first → comma: Kad …, …
Main clause first → usually no comma: …, kad …

Why is the present tense živimo used, even though this feels like a general statement (“whenever we live abroad”)?

Croatian, like English, uses the present tense for:

general truths / habitual situations

Here, Kad živimo u inozemstvu means:

When(ever) we live abroad
Whenever we live abroad / In situations where we live abroad

This is the same use of the present as in English:

When we live abroad, the experience is different.

So živimo (we live) is present tense, but it has a general, habitual meaning, not just “right now at this moment.”