Learn Hardcore Indonesian: Kami mengumpulkan sampah plastik di taman untuk kegiatan daur ulang. - We collect plastic trash in the park for a recycling activity.

In Kami mengumpulkan sampah plastik di taman…, the speaker is saying that their group collects the trash, but the listener is not part of that group.

If the listener were also involved (for example, talking to volunteers before an event), you’d more naturally say:

Kita mengumpulkan sampah plastik di taman untuk kegiatan daur ulang.
= We (you and I, all of us here) collect plastic trash in the park for recycling activities.

What’s the difference between kumpul and mengumpulkan?

kumpul (base verb) means to gather, usually intransitive:
- Kami kumpul di taman. = We gather in the park.
mengumpulkan is meN- + kumpul + -kan and is transitive: to gather/collect something
- Kami mengumpulkan sampah. = We collect trash.

The meN- prefix + -kan suffix often turns a basic verb into a causative or object-focused action:

kumpul (gather) → mengumpulkan (to gather something / to collect)

So here mengumpulkan is used because there is a clear object: sampah plastik.

Why is it sampah plastik and not plastik sampah?

In Indonesian, the general pattern is:

Head noun + modifier

So:

sampah plastik = trash that is plastic → plastic trash
taman kota = city park (park of the city)
kegiatan daur ulang = recycling activity (activity of recycling)

Plastik sampah is not normal Indonesian. If it’s used at all, it would sound strange and unclear, like saying “trash plastic” in English. The natural phrase for “plastic trash” is sampah plastik.

Is sampah plastik singular or plural? Where’s the plural ending?

Indonesian usually does not mark plural with endings like English does. Sampah plastik can mean:

plastic trash (in general)
plastic pieces of trash
plastic rubbish (plural idea from context)

Plural can be shown by:

Context:
- Kami mengumpulkan sampah plastik di taman.
  It’s obviously many pieces.
Reduplication (sometimes):
- sampah-sampah plastik = plastic trash (emphasized as many items), but this sounds a bit unusual or too literal; normally people just say sampah plastik.

So sampah plastik is fine for both singular and plural; context tells you which one.

Why is there no word for the or a before sampah plastik?

Indonesian does not have articles like the, a, or an. The phrase sampah plastik can mean:

the plastic trash
plastic trash
some plastic trash

The exact meaning is understood from context or added words, for example:

sampah plastik itu = that plastic trash / the plastic trash
sampah plastik ini = this plastic trash
beberapa sampah plastik = some plastic trash

But in everyday sentences, just sampah plastik is normal and natural.

How do I know if di here is a preposition (in/at) or part of a passive verb?

In Indonesian, di can be:

A preposition meaning in / at / on
A prefix for passive verbs (attached directly to a verb)

In this sentence:

di taman → di is a preposition, because it’s followed by a noun (taman).

Examples:

Preposition: di taman, di rumah, di Jakarta
Passive verb prefix: dibaca (is read), dibersihkan (is cleaned), dikerjakan (is done)

You can generally tell from spacing:

di taman (preposition + noun, written separately)
dibaca (one word, passive verb)

What exactly does taman mean? Is it “park” or “garden”?

Taman can mean both park and ornamental garden, depending on context:

taman kota = city park
taman rumah = house garden / yard (usually decorative, with plants/flowers)
taman bunga = flower garden

In this sentence, di taman usually suggests a public park, unless context clearly indicates a private garden.

For comparison:

kebun = more like a cultivated garden or field (often for crops, fruit, etc.)
halaman = yard/yard area around a house

What does untuk mean here, and how is it different from agar/supaya or buat?

Untuk usually means for or for the purpose of.

In this sentence:

untuk kegiatan daur ulang = for recycling activities / for the purpose of recycling activities

Compare:

untuk
- noun / noun phrase:
- untuk kegiatan daur ulang = for recycling activities
- untuk anak-anak = for children
untuk
- verb (infinitive-like):
- untuk mendaur ulang = in order to recycle

Agar / supaya usually mean so that and are followed by a clause:

Kami mengumpulkan sampah plastik agar lingkungan menjadi bersih.
= We collect plastic trash so that the environment becomes clean.

Buat is a more informal alternative to untuk:

Kami mengumpulkan sampah plastik di taman buat kegiatan daur ulang.
(colloquial, especially in speech)

Why is it kegiatan daur ulang and not just mendaur ulang?

kegiatan daur ulang is a noun phrase: "recycling activities"
- kegiatan = activity/activities
- daur ulang = recycling
mendaur ulang is a verb: "to recycle"

So:

Kami mengumpulkan sampah plastik di taman untuk kegiatan daur ulang.
= We collect plastic trash in the park for recycling activities (as an organized program/event).

If you want to emphasize the action rather than the “activity” concept, you can say:

Kami mengumpulkan sampah plastik di taman untuk mendaur ulangnya.
= We collect plastic trash in the park to recycle it.

Both are grammatical; they just focus on slightly different things:

kegiatan daur ulang → the program/event
mendaur ulang → the action of recycling

What does daur ulang literally mean?

Daur ulang is a compound:

daur = cycle
ulang = again

So literally it is like “cycle again”, which matches the idea of recycle in English.

Grammatically, daur ulang functions as a noun:

kegiatan daur ulang = recycling activity
program daur ulang = recycling program

The verb to recycle is usually mendaur ulang.

Could you say untuk daur ulang instead of untuk kegiatan daur ulang?

Yes, untuk daur ulang is natural and a bit more concise:

Kami mengumpulkan sampah plastik di taman untuk daur ulang.
= We collect plastic trash in the park for recycling.

This focuses directly on the purpose recycling, without highlighting that it is some kind of organized activity/program.

Nuance:

untuk kegiatan daur ulang → emphasizes organized activities or events
untuk daur ulang → emphasizes the purpose (recycling) more generally

Can I change the word order, for example: Kami mengumpulkan sampah plastik untuk kegiatan daur ulang di taman?

Yes, that alternative is grammatically correct:

Kami mengumpulkan sampah plastik di taman untuk kegiatan daur ulang.
→ More neutral, common order. The place (di taman) comes soon after the verb.
Kami mengumpulkan sampah plastik untuk kegiatan daur ulang di taman.
→ Puts a bit more focus on the purpose (untuk kegiatan daur ulang) before mentioning the place.

In most everyday contexts, both will be understood the same way. Indonesian word order is fairly flexible, as long as you keep phrases together:

di taman stays together
untuk kegiatan daur ulang stays together
No separation inside those chunks.

What’s the formality level of this sentence? Is it formal, informal, or neutral?

The sentence is neutral–formal:

kami, mengumpulkan, sampah plastik, di taman, untuk kegiatan daur ulang
→ all standard, polite Indonesian.

It would sound natural:

in school materials
in NGO or environmental campaigns
in written texts, brochures, or announcements

A more casual version (spoken, among friends) might be:

Kita ngumpulin sampah plastik di taman buat daur ulang.
- kita instead of kami (if speaker includes listener)
- ngumpulin (informal pronunciation of mengumpulkan)
- buat instead of untuk
  But the original sentence is good standard Indonesian.