Learn Hardcore Indonesian: Pengumuman resmi tentang kebijakan itu dibacakan oleh bos. - The official announcement about that policy is read by the boss.

Dibacakan = passive of membacakan: di- + baca + -kan. It means “to be read out (aloud), read for/to someone (an audience).”
Dibaca = passive of membaca (no -kan): “to be read” (can be silently or without implying an audience).
In this context, dibacakan is the idiomatic choice because announcements are typically read out to people.
Examples:
- Pengumuman itu dibacakan (kepada para karyawan). = The announcement was read out (to the employees).
- Buku itu dibaca oleh bos. = The book was read by the boss (not necessarily aloud).

Why use the passive voice here?

Indonesian often fronts the important information (the “thing affected”) using passive, especially in formal/neutral style.
Here, the focus is on the announcement, not on the boss.
Active alternatives:
- Bos membacakan pengumuman resmi tentang kebijakan itu.
- Bos membaca pengumuman resmi tentang kebijakan itu. (less clearly “read aloud”)

Do I need the word oleh to mention the agent?

Standard, with an expressed agent after a di- verb: use oleh.
- Pengumuman … dibacakan oleh bos.
Without the agent: just drop it.
- Pengumuman … dibacakan.
Passive type 2 (no oleh, agent before a bare verb):
- Pengumuman … bos bacakan.
Colloquial speech sometimes drops oleh after di- (e.g., dibacain bos), but avoid this in careful writing.

Can I use membaca instead of membacakan?

Membaca = “to read” (may be silent or general).
Membacakan = “to read (something) out (to someone).”
If the boss read it to an audience, use membacakan:
- Bos membacakan pengumuman … (preferred).
- Bos membaca pengumuman … (grammatical, but may sound like he just read it to himself).

How do I say who it was read to?

Mark the audience with kepada (to/for), or use other phrases:
- … dibacakan kepada para karyawan.
- … dibacakan untuk semua karyawan.
- … dibacakan di depan staf.
Active:
- Bos membacakan pengumuman … kepada para karyawan.

How do I show past, ongoing, or future time?

Indonesian has no tense; use aspect/time markers:
- Completed: … sudah/telah dibacakan …
- Ongoing: … sedang dibacakan …
- Future/planned: … akan dibacakan … / besok … dibacakan …

Why is resmi after pengumuman? Can it go before?

Adjectives usually follow nouns: pengumuman resmi (not resmi pengumuman).
To modify a verb adverbially, use secara resmi:
- Kebijakan itu diumumkan secara resmi.
Both are fine depending on what you want to modify (the noun vs the manner of announcing).

Is tentang the only way to say “about/regarding”?

Neutral/formal synonyms:
- tentang, mengenai
- formal: perihal, terkait (dengan)
- colloquial: soal
Example variants:
- Pengumuman resmi mengenai kebijakan itu …
- Pengumuman resmi terkait kebijakan itu …

Can I say pengumuman kebijakan itu instead of pengumuman tentang kebijakan itu?

Yes:
- Pengumuman kebijakan itu = “the announcement of that policy.”
- Pengumuman tentang/mengenai kebijakan itu = “announcement about/regarding that policy.”
Nuance: without tentang it can feel a bit more “of-phrase”/tighter linkage; with tentang/mengenai it explicitly marks the topic.

What does itu make definite here, and how do I make the announcement itself definite?

In … tentang kebijakan itu, itu makes the policy definite (“that policy”).
To make the announcement definite, put itu after the head noun:
- Pengumuman resmi itu tentang kebijakan tersebut dibacakan …
Formal “the aforementioned”:
- Pengumuman resmi tentang kebijakan tersebut telah dibacakan …

Is bos appropriate here? What are more formal choices?

Where should the oleh-phrase go? Can I move it?

Default: after the passive verb.
- … dibacakan oleh bos.
You can insert short adverbs:
- … dibacakan langsung oleh bos.
Don’t place oleh bos before the verb in this passive; that would force a different structure (active or passive type 2).

How can I emphasize that it was the boss who did it?

Use a cleft/focus construction:
- Yang membacakan pengumuman itu adalah bos.
- Boslah yang membacakan pengumuman itu.
Or add emphasis words:
- … dibacakan langsung oleh bos sendiri.

What are the word-family links behind pengumuman and dibacakan?

umum (public/general) → mengumumkan (to announce) → pengumuman (announcement) [peN- … -an nominalization].
baca (read) → membaca (to read) → membacakan (to read [something] out [to someone]) → dibacakan (passive of membacakan).

Could I rephrase it as “The policy was officially announced by the boss”?

Yes; switch to the policy as subject and use diumumkan:
- Kebijakan itu diumumkan secara resmi oleh bos.
This is often the most natural way to express the same real-world event.