Learn Hardcore Indonesian: Anak-anak mengamati sarang semut di halaman belakang. - The children observe the ant nest in the backyard.

So anak-anak here is best understood as children / the children.
It doesn’t have to be “lots and lots of children”; it can be any plural number (2, 3, etc.).

How do you say the children vs just children in Indonesian? Does anak-anak already mean “the children”?

Indonesian doesn’t have articles like a/an or the.
Anak-anak by itself can mean:

children in general:
- Anak-anak suka bermain. = Children like to play.
the children in a specific context (if the context is clear):
- If we’re already talking about a particular group, anak-anak will be understood as the children.

To make the children more explicit, Indonesians often add:

itu (those/the): anak-anak itu = those children / the children
a possessor: anak-anak kami = our children

In your sentence, Anak-anak mengamati…, it’s naturally interpreted as The children were observing…, because the context usually makes it specific.

What’s the nuance of mengamati? How is it different from melihat or menonton?

All three involve looking, but with different nuances:

melihat = to see / to look (at)
Neutral, everyday word:
- Saya melihat burung. = I see a bird.
menonton = to watch (usually something like TV, movies, performances)
- Kami menonton film. = We watch a movie.
mengamati = to observe / to examine carefully
Suggests focused, often somewhat systematic observation:
- Anak-anak mengamati sarang semut.
  = The children are observing / studying the anthill, not just glancing at it.

So mengamati in your sentence implies the children are looking at the anthill carefully, maybe with curiosity or for learning.

There’s no word for was / were. How do we know if this is past or present? How do you say “were observing” vs “are observing”?

Indonesian verbs do not change form for tense (past, present, future).
Mengamati is literally just observe, without time information.

The time is normally shown by:

context
time words: tadi (earlier), kemarin (yesterday), besok (tomorrow), etc.
aspect markers like sedang, sudah, akan

Examples based on your sentence:

Anak-anak mengamati sarang semut di halaman belakang.
= The children observe / are observing / were observing the anthill in the backyard.
(tense depends on context)
Anak-anak sedang mengamati sarang semut di halaman belakang.
= The children are (currently) observing the anthill.
Tadi anak-anak mengamati sarang semut di halaman belakang.
= Earlier, the children were observing the anthill in the backyard.

So your original sentence is tense-neutral; English speakers usually add tense based on context.

Why is it sarang semut and not something like sarang dari semut for “nest of ants”?

In Indonesian, the common way to express “X of Y” (possessive or descriptive) is:

[thing] + [owner / classifier]

So:

sarang semut = nest (of) ants
rumah saya = my house
buku guru = the teacher’s book / a teacher’s book

You usually do not say sarang dari semut for a normal “ants’ nest”.
dari (“from/of”) is used more for:

origin/material: meja dari kayu = a table made of wood
starting point: datang dari Jakarta = come from Jakarta

So sarang semut is the natural way to say anthill / ants’ nest.

Why isn’t semut also pluralized? Why not sarang semut-semut to show “ants”?

Plural is often left unmarked in Indonesian if it’s obvious from context or simply not important.

sarang semut is naturally understood as nest of ants (there’s always more than one ant in a nest).
Saying sarang semut-semut is grammatically possible, but it sounds strange and usually unnecessary. It might sound like you’re emphasizing many different ants or kinds of ants.

Common patterns:

Plural marked only on the first noun:
- anak-anak sekolah = school children
Plural not marked at all (most common):
- banyak semut = many ants (plural shown by banyak, not by reduplication)

So sarang semut is the natural, standard form.

In halaman belakang, which word is which? Why isn’t it belakang halaman?

halaman = yard / yard area (can be front or back yard, school yard, etc.)
belakang = back / behind

Word order rule: describing words (adjectives, position words used like adjectives) usually come after the noun.

So:

halaman belakang = back yard / the yard at the back
(halaman = yard, belakang = describing which part)

If you say belakang halaman, it would literally be “the back of the yard,” and even then Indonesians would normally say:

bagian belakang halaman = the back part of the yard

So for “the backyard,” you want halaman belakang, not belakang halaman.

What’s the difference between di halaman belakang and ke halaman belakang?

di = at / in / on (static location, where something is)
ke = to / towards (movement to a place)

In your sentence:

di halaman belakang = in the backyard / at the backyard
(location: that’s where the observing happens)

If you want to express movement:

Anak-anak berjalan ke halaman belakang.
= The children walk to the backyard.

So for “observing in the backyard,” di is the correct preposition.

Is the hyphen in anak-anak necessary? How are reduplicated words usually written?

Yes, according to standard Indonesian spelling rules, full reduplication is written with a hyphen:

anak-anak = children
buku-buku = books
rumah-rumah = houses

If you leave the hyphen out (anakanak), it’s considered incorrect or at least nonstandard.

There are some words that used to be reduplications but are now fixed as single words in the dictionary, but in general, for regular plural reduplication, always use the hyphen.

Can I say Anak-anak sedang mengamati sarang semut di halaman belakang? Is that more natural?

Yes, that’s perfectly natural and very clear.

Anak-anak mengamati…
= The children observe / were observing (time is not specified)
Anak-anak sedang mengamati…
= The children are currently observing / are in the middle of observing…

Adding sedang emphasizes that the action is happening right now, similar to English “are (in the process of) observing.”

Both sentences are correct; sedang is used when you specifically want to highlight the ongoing nature of the action.

Could I change the word order to start with sarang semut, like Sarang semut diamati anak-anak di halaman belakang? Would that be correct?

Yes, that’s also correct, but it changes the voice and the emphasis.

Your original sentence is active voice:

Anak-anak mengamati sarang semut di halaman belakang.
= The children observe the anthill in the backyard.

Sarang semut diamati anak-anak di halaman belakang. is passive voice:

diamati = di- (passive prefix) + amati
Literally: “The anthill is observed by the children in the backyard.”

Nuance:

Active (mengamati) is more common in everyday speech.
Passive with di- (diamati) sounds more formal or written, and it puts sarang semut in the topic/subject position: “As for the anthill, it was observed by the children…”

So it’s grammatically correct, but stylistically different.

Could we drop di and just say Anak-anak mengamati sarang semut halaman belakang?

No, that would be unnatural and confusing.

You normally need a preposition before a noun that expresses location:

di halaman belakang = in the backyard
di sekolah = at school
di rumah = at home

Without di, halaman belakang just looks like another noun phrase attached to sarang semut, and the structure stops making sense.

So the correct, natural form is:

Anak-anak mengamati sarang semut di halaman belakang.

Is halaman belakang always “backyard of a house”, or can it be something else?

Halaman belakang literally means the back yard/area, and it depends on context:

For a house: usually understood as backyard.
For a school or office: it can mean the back yard/area of that building.

If you want to be very explicit that it’s the backyard of a house, you can say:

di halaman belakang rumah = in the backyard of the house
di halaman belakang rumah kami = in our backyard

In everyday conversation, halaman belakang by itself is often enough, and people infer from context whose backyard it is.