Learn Hardcore Indonesian: Guru menyampaikan pengumuman resmi di ruang kelas. - The teacher delivers an official announcement in the classroom.

If the listener already knows which teacher and which announcement, you understand it as “the teacher” / “the announcement”.
If it’s new information, you understand it as “a teacher” / “an announcement”.

If you really need to make something clearly definite, you can add itu (that):

Guru itu menyampaikan pengumuman resmi… = That / the (specific) teacher delivered an official announcement…

What exactly does guru mean? Is it only a school teacher?

Guru in Indonesian generally means teacher, but with some typical nuances:

Most commonly, it refers to a school teacher (especially at elementary, middle, or high school level).
It can sometimes be used for other types of teachers (e.g. guru musik = music teacher), but for university, people usually say dosen (lecturer).
It does not show gender; guru can be male or female.

Examples:

Guru bahasa Inggris = English teacher
Guru SD = elementary school teacher
Dosen bahasa Inggris = English lecturer (at university), usually not called guru in that context.

What is the base form of menyampaikan, and what do the prefixes/suffixes mean?

The word menyampaikan comes from the base sampai.

sampai = to arrive, to reach, until (intransitive)
sampaikan = to cause something to reach someone → to convey / to deliver (a message)
- This is formed by adding -kan to sampai, giving a causative idea: make [something] reach [someone].
menyampaikan = active verb, to deliver / to convey / to communicate (something)
- meN- is an active verb prefix. With a base starting with s, meN- becomes meny- (a regular sound change).

So structurally:

meN- + sampaikan → menyampaikan = to deliver / to convey (something)

In the sentence, Guru menyampaikan pengumuman…, the teacher is actively delivering the announcement.

Why do we say menyampaikan pengumuman and not just use a verb like mengumumkan?

Both patterns exist and are correct, but they are slightly different:

menyampaikan pengumuman
- Literally: to deliver an announcement
- Structure: [verb] + [noun]
- Emphasizes the act of passing on / delivering an already existing announcement.
mengumumkan [something]
- Literally: to announce [something]
- Structure: [verb] + [object]
- Emphasizes the act of announcing the content itself.

Examples:

Guru menyampaikan pengumuman resmi di ruang kelas.
The teacher delivered an official announcement in the classroom.
Guru mengumumkan peraturan baru di ruang kelas.
The teacher announced the new rules in the classroom.
(Here peraturan baru = what is being announced.)

Using mengumumkan in your exact sentence would sound incomplete unless you add what is being announced:

Guru mengumumkan… apa? → You need an object (e.g. peraturan baru, hasil ujian, etc.).

What does pengumuman come from, and what does the pattern peN- -an mean?

The noun pengumuman comes from the root umum:

umum = general, public
mengumumkan = to announce something to the public
pengumuman = announcement (the thing that is announced)

pengumuman is formed with the noun-forming pattern peN- -an:

peN-
- ROOT
  - -an → usually a noun related to an action
Some common examples:
- makan (to eat) → pemakanan (feeding, less common), makanan (food, from meN- + makan + -an historically)
- ajar (to teach) → pengajaran (teaching, instruction)
- umum → pengumuman (announcement)

So pengumuman is the announcement itself, not the act of announcing.

Why is it pengumuman resmi and not resmi pengumuman?

In Indonesian, the usual order inside a noun phrase is:

Noun + Adjective

So:

pengumuman resmi = official announcement
ruang kelas besar = a big classroom

Putting the adjective first (resmi pengumuman) is not correct as a normal noun phrase.

If you really want to emphasize the adjective, you might say:

pengumuman yang resmi = an announcement that is official

But the normal, natural form is pengumuman resmi.

What is the difference between ruang kelas and just kelas?

Both can be translated as “classroom” in some contexts, but they are not identical:

ruang kelas
- Literally: class room (room for a class)
- Focuses on the physical room (the space).
- More precise when you want to emphasize location.
- Example: Kami belajar di ruang kelas 3A.
kelas
- Has several meanings:
  - classroom
  - class group (the people in the class)
  - grade/level (e.g. kelas 5 = 5th grade)
- In speech, di kelas often means in the classroom, but it can be a bit more general.

In your sentence:

di ruang kelas clearly focuses on the room as the place where the announcement is given.
di kelas would also be commonly used and understood as in class / in the classroom, and is more casual.

How is di used here, and when would you use ke or pada instead?

In di ruang kelas, di is a location preposition meaning “in / at”.

di = in / at / on (static location)
- di rumah = at home
- di sekolah = at school
- di ruang kelas = in the classroom

Compare:

ke = to (movement/direction toward a place)
- pergi ke sekolah = go to school
- masuk ke ruang kelas = enter the classroom
pada = used more with time or an abstract recipient/target
- pada hari Senin = on Monday
- berbicara pada guru = speak to the teacher (more formal; often replaced by kepada)

So in this sentence, because we’re talking about where the action happens (not movement), di is the correct choice.

Can we move di ruang kelas to the front of the sentence? Does the meaning change?

Yes, you can change the word order without changing the basic meaning:

Guru menyampaikan pengumuman resmi di ruang kelas.
Di ruang kelas, guru menyampaikan pengumuman resmi.

Both mean the same thing. The difference is emphasis:

Original order: neutral; focuses first on who (the teacher) and what they did.
Di ruang kelas, …: puts a little more emphasis on the location (“In the classroom, the teacher delivered…”).

This kind of fronting is common in Indonesian and is grammatically fine. Just add a comma in writing.

How do we know if this sentence is in the past, present, or future?

Indonesian verbs like menyampaikan do not change form for tense. The same form can mean:

The teacher delivered an official announcement (past)
The teacher is delivering an official announcement (present)
The teacher will deliver an official announcement (future, but less common without markers)

The time is usually shown by time words or context, for example:

Tadi pagi guru menyampaikan pengumuman resmi di ruang kelas.
This morning the teacher delivered an official announcement… (past)
Sekarang guru menyampaikan pengumuman resmi di ruang kelas.
Now the teacher is delivering an official announcement… (present)
Besok guru akan menyampaikan pengumuman resmi di ruang kelas.
Tomorrow the teacher will deliver an official announcement… (future)

Without such words, you rely on context. Native speakers fill in the tense automatically.

Does this sentence sound formal? How would it sound in more casual language?

The sentence Guru menyampaikan pengumuman resmi di ruang kelas. is on the formal / neutral side:

menyampaikan pengumuman resmi sounds like school or official language (announcements, regulations, etc.).

In more casual spoken Indonesian, people might say something like:

Bu Guru ngasih pengumuman penting di kelas.
- Bu Guru = female teacher (“Mrs./Ms. Teacher”)
- ngasih (from memberi / ngasih tahu) = give / tell (colloquial)
- pengumuman penting = important announcement
- di kelas = in class

You can adjust formality by:

Choosing verbs: menyampaikan (formal) vs ngasih tahu / bilang (informal “tell, say”)
Choosing nouns: keeping pengumuman resmi is still fine in casual contexts, but pengumuman penting may feel a bit less bureaucratic in some situations.