Learn Hardcore Indonesian: Kerumunan penumpang menunggu di peron sambil memotret langit senja. - A crowd of passengers waits on the platform while photographing the dusk sky.

kerumunan is a noun meaning crowd or gathering, formed by adding the suffix -an to the root kerumun (to cluster). In this sentence it is the head noun, indicating that we’re talking about a crowd as a single group.

Why is it kerumunan penumpang and not penumpang kerumunan?

In Indonesian the head noun comes first, followed by its modifier. Here the head is kerumunan (the crowd) and penumpang (passengers) tells us whose crowd it is. Reversing them would break the usual noun-modifier order.

How do we know penumpang is plural when there’s no -s ending?

Indonesian does not mark plurality with an -s. A noun like penumpang can be singular or plural; you rely on context. Because kerumunan means a crowd, we infer many passengers. If you want to be explicit you can say para penumpang or penumpang-penumpang, but it’s not required.

What does di mean in di peron, and why not use ke or pada?

di is a locative preposition meaning at or on, marking the place where the action happens: waiting at the platform.

ke means to (toward), indicating movement.
pada is a more formal preposition often used with time or abstract relations, not location-of-action.

Does the verb menunggu indicate tense? Is it correct without sedang?

Verbs in Indonesian do not change form for tense. menunggu can mean wait, is waiting, was waiting, or will wait—all determined by context. Adding sedang (currently) makes the progressive explicit (sedang menunggu = is waiting), but it’s optional.

What function does sambil serve in the sentence?

sambil means while, linking two simultaneous actions carried out by the same subject. Here it connects waiting and photographing: they are waiting on the platform while taking pictures of the evening sky.

Why is the verb after sambil in its me- form (memotret) and not changed further?

Indonesian verbs don’t conjugate for person, number, or tense. After sambil you use the verb in its normal active form. memotret is just the standard active form ‘to photograph’.

Why is it memotret and not mengpotret or memfotret?

This follows the me- prefix assimilation rules. The base is potret (from Dutch). When me- attaches to a word starting with p, the initial p is dropped and the prefix becomes mem-. Thus me + potret → memotret.

In langit senja, why does langit come before senja? Could it be senja langit?

Indonesian places the head noun first, followed by its modifier. Here langit (sky) is the head and senja (dusk/evening) describes the kind of sky. senja langit inverts that order and sounds unnatural.

Could we use sementara or ketika instead of sambil to mean while?

You can use sementara and ketika, but they introduce full clauses, not a direct verb phrase. Example:

sementara kerumunan penumpang menunggu…
ketika kerumunan penumpang menunggu…
In contrast, sambil goes straight into a verb phrase (sambil memotret…) to show two actions happening at once by the same subject.