Learn Hardcore Indonesian: Polisi berpatroli di lingkungan kami setiap malam. - The police patrol in our neighborhood every night.

Polisi berpatroli di lingkungan kami.
= The police patrol in our neighborhood. (clear verb)
Polisi patroli di lingkungan kami.
This is understandable and you might hear it in speech, but it sounds more colloquial and a bit less standard; it feels like using the noun patroli as a verb, influenced by English.

More formal alternatives:

Polisi melakukan patroli di lingkungan kami. (literally “do a patrol”)
Polisi sedang patroli di lingkungan kami. (colloquial: “are on patrol in our neighborhood”)

For standard Indonesian, berpatroli is the safest neutral choice.

Is Polisi singular or plural here?

In Indonesian, polisi can mean:

a police officer (singular)
the police (as a group/institution) (collective)

In this sentence, Polisi berpatroli… is most naturally understood as “The police (as a group) patrol…”.

If you specifically want plural, you can say:

Para polisi berpatroli… (a group of police officers)
Polisi-polisi berpatroli… (reduplication, also plural, often more informal or emphasizing many individuals)

If you want to stress one officer:

Seorang polisi berpatroli… (a police officer patrols…)

Why is there no word like “the” or “a” before Polisi?

Indonesian does not use articles like a / an / the.

The bare noun polisi can correspond to:

“a police officer”
“the police”
“police officers” (in general)

Context decides which English article you use in translation. You don’t add anything in Indonesian; polisi alone is enough.

Why is there no subject pronoun like “they” in the sentence?

In Indonesian, when the subject is a noun, you usually don’t add an extra pronoun.

English:

The police, they patrol our neighborhood… (possible, but redundant)

Indonesian:

Polisi berpatroli di lingkungan kami… (subject = Polisi; no need to add mereka)

Saying Polisi mereka berpatroli… would be wrong or at least very unnatural in this context. The noun Polisi already functions as the subject.

What does lingkungan mean here? Does it mean “environment” or “neighborhood”?

Lingkungan can mean several related things, depending on context:

Neighborhood / local area – the most natural meaning here.
- di lingkungan kami = in our neighborhood / in our area
Environment / surroundings – in more general or abstract contexts.
- lingkungan kerja = work environment
- lingkungan hidup = (natural) environment

In this sentence, with police patrolling and kami (“we/our”), the meaning is clearly our residential area / neighborhood.

Why is kami used instead of kita?

Both mean “we / us / our”, but:

kami = we (not including the listener)
kita = we (including the listener)

Lingkungan kami means “our neighborhood (not yours)” or at least, the speaker is not explicitly including the person they’re talking to.

If the speaker wants to include the listener (for example you both live there), they could say:

Polisi berpatroli di lingkungan kita setiap malam.
= The police patrol our neighborhood (yours and mine) every night.

In textbooks, this kami vs kita distinction is very important and quite consistent.

Is lingkungan kami the normal way to say “our neighborhood”? Can we say it another way?

Yes, lingkungan kami is the normal, natural way.

Structure:

lingkungan (neighborhood)
kami (our)
→ possessor comes after the noun.

Other possible ways:

lingkungan kami = our neighborhood (standard, concise)
lingkungan rumah kami = the neighborhood around our house (more specific)
daerah kami = our area / region (broader and less specific than neighborhood)

You wouldn’t normally say kami punya lingkungan for this meaning; that sounds like “we own an environment,” which is odd. Use lingkungan kami instead.

Can we move setiap malam to another position, like Polisi berpatroli setiap malam di lingkungan kami?

Yes, that is also grammatical, and the meaning is the same:

Polisi berpatroli di lingkungan kami setiap malam.
Polisi berpatroli setiap malam di lingkungan kami.

Both are fine. The first version (time at the end) is probably more common in this exact sentence.

Indonesian word order is relatively flexible, especially for time and place phrases. Changing the position slightly can add a small emphasis, but here there’s no big change in meaning.

What does setiap malam mean exactly? Is it the same as tiap malam?

setiap malam = every night
tiap malam = basically the same, every night

Differences:

setiap is a bit more formal/neutral.
tiap is slightly more informal/colloquial, very common in speech.

You could say:

Polisi berpatroli di lingkungan kami tiap malam.
This is natural and correct.

Another variant:

setiap malamnya adds a slight nuance of “each night (in that context / that particular place),” but you usually don’t need -nya here.
Setiap malam is perfectly good.

Is there any tense marking in berpatroli? How do we know it means a habitual action like “patrol every night”?

Indonesian verbs do not change form for tense (no -ed, -s, etc.).

Berpatroli has the same form for:

past: “patrolled”
present: “patrol / are patrolling”
future: “will patrol”

We know it is habitual here because of setiap malam (“every night”): that phrase gives the time pattern and implies a regular, repeated action.

If you wanted to add more explicit time information, you could use:

dulu (used to, in the past):
Dulu polisi berpatroli di lingkungan kami setiap malam.
akan (will, future):
Mulai bulan depan, polisi akan berpatroli di lingkungan kami setiap malam.

Why do we need di before lingkungan kami? Could we say Polisi berpatroli lingkungan kami?

You need the preposition di to express location (“in / at / on”):

di lingkungan kami = in our neighborhood

Without di, it becomes ungrammatical or unclear:

Polisi berpatroli lingkungan kami ❌ (wrong)

In Indonesian:

di = at/in/on (location)
ke = to (movement towards a place)
dari = from (movement away from a place)

Here it’s about where the patrol happens, so di is required.