Learn Hardcore Indonesian: Lampu yang berkedip diganti sore ini, sebab rapat malam harus tenang. - The blinking light is being replaced this afternoon, because the evening meeting must be calm.

Yang turns the following clause into a modifier of a noun, like English “that/which.” So lampu yang berkedip = “the lamp(s) that are blinking.” Use yang when the modifier is a whole clause or has its own predicate.

No yang is needed for simple adjectives: lampu baru (a new lamp).
You do need yang for verb-like modifiers: orang yang lewat (the person who passed by).

Is berkedip the right verb for a light? Isn’t berkedip for eyes?

Yes, berkedip works for lights too and is common in Indonesian. You may also see:

berkedip-kedip (repeated/flickering feel, a bit more vivid)
kelap-kelip / berkelap-kelip (twinkling/flickering, a bit descriptive or literary) All are acceptable; berkedip is neutral and fine here.

Why is diganti in the passive? Who is doing the replacing?

Indonesian often uses the passive (di-) when the agent is obvious or unimportant. Diganti focuses on the lamp as the thing affected. If you want to mention the doer:

With an agent: Lampu yang berkedip diganti sore ini oleh teknisi.
Active voice: Teknisi mengganti lampu yang berkedip sore ini.

Do I need akan to show the future (will be replaced)?

Not necessarily. Indonesian relies on time expressions. Sore ini already places it in the near future/today. Add markers only if you want extra clarity:

Planned: Lampu … akan diganti sore ini.
Already done: Lampu … sudah/tadi sore diganti.

Is the comma before sebab required?

It’s optional. You can write:

Lampu … diganti sore ini, sebab rapat malam harus tenang.
Lampu … diganti sore ini sebab rapat malam harus tenang. Both are fine. You can also front the reason: Sebab rapat malam harus tenang, lampu … diganti sore ini.

What’s the difference between sebab and karena?

Both mean “because.”

karena: neutral, very common in speech and writing.
sebab: a bit more formal/literary. Colloquial alternative: soalnya (because/the reason is). For results, use makanya or oleh karena itu, not sebab.

Does rapat malam mean tonight’s meeting or just meetings held at night?

Rapat malam literally “night meeting,” so it can be generic. If you specifically mean tonight’s meeting, say rapat malam ini. In your sentence, context plus sore ini implies “tonight,” but adding ini removes ambiguity.

What time of day is sore compared to malam?

sore: late afternoon to early evening (roughly 3–6/7 pm).
malam: evening/night (after sunset). So replacing the lamp sore ini fits a quiet rapat malam later the same day.

Is harus tenang the best phrasing? Could I say hening, sunyi, tertib, or use a verb?

Harus tenang (must be calm/quiet) is natural. Alternatives:

More formal/process-oriented: rapat malam harus berlangsung dengan tenang / berjalan dengan tertib.
Nuances:
- tenang: calm, not noisy/agitated.
- hening: very quiet, often with a solemn feel.
- sunyi/sepi: quiet due to emptiness/few people (not quite what you want for a meeting).
- tertib: orderly, disciplined.

Is lampu singular or plural here?

Indonesian doesn’t mark plural by default, so lampu could be “lamp” or “lamps.” Specify if needed:

One: sebuah lampu / satu lampu.
Several: beberapa lampu / lampu-lampu (reduplication is possible but often avoided in everyday speech in favor of quantifiers like beberapa).

Why diganti and not digantikan?

Use:

diganti (dengan …) when something is replaced (by someone), optionally stating what it’s replaced with: Lampu itu diganti dengan bohlam LED.
digantikan (oleh …) when you present the new thing/person as the replacer: Lampu itu digantikan oleh bohlam LED. Both are grammatical, but with objects, diganti (dengan …) is the more common pattern.

Can I move sore ini elsewhere in the sentence?

Yes, time adverbs are flexible:

Sore ini, lampu yang berkedip diganti, sebab …
Lampu yang berkedip akan diganti sore ini, sebab …
Lampu yang berkedip diganti sore ini sebab … Avoid putting sore ini right after berkedip if it could attach to the wrong unit: Lampu yang berkedip sore ini… may be misread as “the lamp that blinks this afternoon.”

How would I say this in active voice?

Examples:

Kami akan mengganti lampu yang berkedip sore ini, karena/sebab rapat malam harus tenang.
Teknisi mengganti lampu yang berkedip sore ini, karena rapat malam harus tenang.

How do Indonesians express “the” or “a/the” with lampu here?

Indonesian has no articles. Definiteness comes from context or markers:

Definite/specific: lampu itu (that/the lamp), lampu yang berkedip (the one(s) that blink).
Indefinite: sebuah lampu (a lamp), beberapa lampu (some lamps).

Could I use agar/supaya instead of sebab to express purpose?

Yes, if you want to frame it as purpose (so that), not cause (because):

Lampu yang berkedip diganti sore ini agar/supaya rapat malam tenang.
Cause (original): … diganti … sebab/karena rapat malam harus tenang. Both are fine; choose based on whether you want “because” (reason) or “so that” (goal).

Why is there no “be” before tenang? Should it be “be quiet”?

In Indonesian, adjectives can function as predicates without a copula. Rapat malam harus tenang literally “The night meeting must quiet,” which in English is “must be quiet.” The be is simply not used in Indonesian in this structure.