Learn Hardcore Croatian: Susjed koji živi iznad nas radi na računalu. - The neighbor male who lives above us works on the computer.

Koji is a relative pronoun meaning “who/that/which.” It agrees in gender and number with the noun it refers to, here susjed (masculine singular), so we use koji.

Feminine: susjeda koja živi…
Neuter: dijete koje živi…
Plural (masc. personal): susjedi koji žive…

What case is nas in iznad nas, and why?

It’s genitive. The preposition iznad (“above”) always takes the genitive, so the pronoun mi becomes nas in genitive: iznad nas = “above us.” Compare:

iznad nas (genitive, with iznad)
nad nama (instrumental, with nad)

Why is it na računalu and not na računalo?

Because na takes the locative for static location and the accusative for motion onto a surface.

Static: radi na računalu (“is working on/at the computer”) → locative: računalu
Motion: stavljam knjigu na računalo (“I’m putting the book onto the computer”) → accusative: računalo

Could I also say za računalom or s računalom? What’s the difference?

raditi na računalu = working on/at a computer (using it).
raditi za računalom = sitting/positioned at a computer (physical position at the desk).
raditi s računalom = work with a computer (as a tool/skill area). All are possible; choose based on nuance.

Does radi mean “is working” or “works”? How do Croatians express the continuous?

Both. Croatian present (imperfective) covers ongoing and habitual:

“is working (right now)” or “works (in general).” To make it clearly ongoing, add an adverb: sada/trenutno/upravo: Susjed … trenutno radi na računalu.

Is the relative pronoun koji in the nominative here?

Yes. Inside the relative clause, koji is the subject of živi, so it’s nominative. If the pronoun played a different role, its case would change:

Accusative (fem.): Susjeda koju smo vidjeli…
Genitive (masc.): Susjed kojeg(a) znam…
Dative/Locative: Susjedu kojem(u)/kome pomažem…
Instrumental: Susjed s kojim radim…

Can I put commas around the relative clause?

Both are possible, but they mean different things:

Susjed koji živi iznad nas radi… (no commas) = restrictive: the neighbor who lives above us (as opposed to some other neighbor).
Susjed, koji živi iznad nas, radi… (commas) = non‑restrictive: there’s only one relevant neighbor; the clause is just extra info.

What are the gender forms for “neighbor” and how does that affect the sentence?

Masculine: susjed → Susjed koji živi…
Feminine: susjeda → Susjeda koja živi…
Plural: susjedi → Susjedi koji žive… The relative pronoun (koji/koja/koji) and the verb (živi/žive) agree accordingly.

Could I say kompjuter or računar instead of računalo?

Yes, depending on variety and register:

Standard Croatian: računalo (locative: na računalu)
Colloquial in Croatia: kompjuter (locative: na kompjuteru)
Serbian/Bosnian: računar (locative: na računaru) Choose based on audience and context.

Is the word order fixed? Can I move parts of the sentence around?

Croatian word order is flexible, but you must keep the relative clause attached to its noun:

Neutral: Susjed koji živi iznad nas radi na računalu.
Focus on activity: Radi na računalu susjed koji živi iznad nas.
Front the location: Iznad nas živi susjed koji radi na računalu. Wrong: Susjed radi na računalu koji živi iznad nas. (misattaches the clause)

Why are there no articles like “the” in Susjed?

Croatian has no articles. Definiteness/indefiniteness is inferred from context. If you want to be explicit, use a demonstrative:

Taj susjed (“that neighbor”)
Naš susjed (“our neighbor”)

Pronunciation tips for tricky letters?

ž as in “meaSure”: živi → ZHEE‑vee
č like “ch” in “church”: računalu → rah‑CHOO‑nah‑loo
j sounds like English “y”: koji → KO‑yee
sj in susjed is like an “s” with a quick “y”: SOO‑syed

Could raditi na računalu mean “to be working on developing/fixing a computer”?

Context decides. In everyday speech, raditi na računalu means “work on/at a computer (use it).” If you mean repairing/developing it, say:

popravlja računalo (is repairing the computer)
radi na popravku računala (is working on the repair of the computer)

What’s the difference between iznad and nad in this context?

Both mean “above,” but they take different cases and have slightly different feel:

iznad
- genitive: iznad nas (spatially higher than us; common for “the apartment above”)
nad
- instrumental: nad nama (physically over/above; also used metaphorically: nad gradom “over the city”)

Why does računalo become računalu?

It’s the locative singular ending for a neuter noun. Minimal singular forms:

Nominative: računalo
Genitive: računala
Dative/Locative: računalu
Accusative: računalo
Instrumental: računalom

Can I use stanuje instead of živi?

Yes. Živi = “lives” (general), stanuje = “resides” (more about dwelling in a particular apartment/building). Both fit here:

Susjed koji stanuje iznad nas…