Learn Hardcore Indonesian: Pernikahan kecil itu akan diadakan di rumah, sedangkan resepsi diadakan di gedung dekat kantor. - That small wedding will be held at home, while the reception is held in a building near the office.

pernikahan kecil itu ≈ “that small wedding” / “the small wedding”
Without itu: pernikahan kecil is more like “a small wedding” (less specific).

There’s no itu after resepsi because the speaker doesn’t need to mark it as specifically as the wedding, or the context already makes it clear. You could say:

… sedangkan resepsi itu diadakan di gedung dekat kantor.

That would make both the wedding and the reception explicitly “that (particular) one.” It’s a nuance choice, not a strict rule.

Why is the adjective kecil placed after pernikahan instead of before it?

In Indonesian, descriptive adjectives usually come after the noun:

pernikahan kecil = small wedding
gedung besar = big building
rumah baru = new house

So pernikahan kecil is the normal word order.
The pattern is generally:

noun + adjective
e.g. resepsi sederhana (simple reception), kantor pusat (head office)

Why use the passive akan diadakan instead of an active form like kami akan mengadakan?

Diadakan is the passive form of mengadakan (“to hold / to organize”). Indonesian often uses the passive to focus on the event, not the doer.

Pernikahan kecil itu akan diadakan di rumah.
→ Focus: the wedding and where it will be held.
Kami akan mengadakan pernikahan kecil itu di rumah.
→ Focus: we as the organizers.

In this kind of informational sentence (explaining plans, announcements, invitations), the passive diadakan is very natural and common.

Why is akan used in the first clause (akan diadakan) but not repeated in the second clause (resepsi diadakan)? Is the second one still future?

Yes, the second event is still understood as future.

In Indonesian, when two clauses are closely connected, a word like akan can be stated once and then understood for the next clause:

Pernikahan kecil itu akan diadakan di rumah, sedangkan resepsi (akan) diadakan di gedung dekat kantor.

Adding akan to the second clause is grammatically fine and maybe a bit clearer, but leaving it out is very natural and avoids repetition. Context and the parallel structure tell the listener it’s also future.

What is the difference between sedangkan and just using dan? Could I say … di rumah, dan resepsi diadakan…?

You can say dan, but it’s slightly different in nuance.

dan = and (just adding information)
sedangkan = whereas, while, on the other hand (showing contrast or difference)

In this sentence:

… di rumah, sedangkan resepsi diadakan di gedung dekat kantor.

Sedangkan highlights a contrast:
→ the ceremony is at home, whereas the reception is at a hall.

If you say:

… di rumah, dan resepsi diadakan di gedung dekat kantor.

it’s grammatically correct but feels more like you’re just listing two facts, with less emphasis on the contrast.

Why is there no subject like we or they? Who is doing the action?

Indonesian often omits the subject when it’s obvious or not important.

Pernikahan kecil itu akan diadakan di rumah.
Literally: That small wedding will be held at home.
The doer (we/they/someone) is not mentioned.

The sentence focuses on what happens to the wedding, not who arranges it. If you really want to specify:

Kami akan mengadakan pernikahan kecil itu di rumah.
(We will hold that small wedding at home.)
Mereka akan mengadakan resepsi di gedung dekat kantor.
(They will hold the reception at the building near the office.)

What exactly does di rumah mean here? Does it mean “at my house,” “our house,” “the house,” or something else?

Di rumah literally means “at home” or “at the house.”
Whose house it is depends on context:

If the speaker is talking about their own wedding, di rumah is usually understood as at (our/my) house.
In more neutral narration, it can just be “at a house” instead of a public venue.

If you want to be explicit:

di rumah kami = at our house
di rumah orang tua saya = at my parents’ house
di rumah mereka = at their house

But in everyday speech, di rumah alone very often implies at (our/my) house when it’s clear from context.

How should I understand the structure di gedung dekat kantor? What is modifying what?

Break it down:

di = at / in
gedung = building / hall
dekat = near
kantor = office

The structure is:

di + [gedung dekat kantor]

Gedung dekat kantor means:

a building near the office or
the hall near the office (depending on context)

So dekat kantor functions like an adjective phrase modifying gedung:

gedung dekat kantor = the building that is near the office

How does dekat work here? Is it like a preposition or an adjective?

In gedung dekat kantor, dekat behaves like an adjective or spatial descriptor that takes a noun after it:

dekat kantor = near the office
dekat rumah = near the house

You may also see forms like:

gedung yang dekat kantor (more explicit: the building that is near the office)
gedung dekat dengan kantor (adds dengan, still natural)

But gedung dekat kantor is the most concise and very natural in speech and writing.

What’s the difference between pernikahan and resepsi? Aren’t both “wedding”?

They refer to different parts of what English often groups as “a wedding”:

pernikahan = the marriage ceremony itself (the formal, often religious/legal event when the couple is officially married).
resepsi (pernikahan) = the reception or party afterward (food, guests, celebration).

So this sentence is saying:

The ceremony will be at home,
The reception/party will be at a hall near the office.

You can say resepsi pernikahan to make it explicit that it’s a wedding reception.

Could I say pernikahan kecil itu akan berlangsung di rumah instead of akan diadakan di rumah? What’s the nuance difference?

Yes, you can, and it’s natural, but there’s a subtle difference:

diadakan = to be held / to be organized
→ emphasizes that someone arranges/hosts the event.
berlangsung = to take place / to occur
→ emphasizes the event simply happening somewhere.

So:

Pernikahan kecil itu akan diadakan di rumah.
→ Focus on the arrangement/hosting of the wedding at home.
Pernikahan kecil itu akan berlangsung di rumah.
→ Focus on the wedding taking place at home.

Both are correct; diadakan is slightly more about organizing, berlangsung slightly more neutral about location/time.

What level of formality is this sentence? Is it suitable for casual speech?

This sentence is in neutral–formal Indonesian:

Vocabulary like pernikahan, resepsi, diadakan, sedangkan is perfectly fine in:
- invitations
- written announcements
- polite conversation

In casual speech, people might simplify slightly, but still say something very similar:

Nanti nikah kecilnya di rumah, resepsinya di gedung dekat kantor.
Pernikahannya di rumah, resepsinya di gedung dekat kantor.

The original version is fully natural for both spoken and written Indonesian, especially when explaining plans politely.