Learn Hardcore Indonesian: Betapa gelapnya langit mendung sebelum petir! - How dark the overcast sky is before lightning!

Turns the adjective into an exclamatory/nominalized form (“how dark it is / the darkness”).
Is required with betapa in standard exclamations: Betapa + ADJ-ny(a) + (subject).
It is not a possessive “its” here.

Compare:

Betapa indahnya pemandangan ini! = “How beautiful this view is!”

Can I omit -nya and say Betapa gelap langit mendung …?

Not in standard usage. With betapa + adjective, Indonesian strongly prefers (and most style guides require) the -nya: Betapa gelapnya …. Omitting it can sound poetic or nonstandard.

Is betapa a question word like “how?” that expects an answer?

No. In this use it’s exclamatory, not interrogative. Don’t use a question mark. It can also introduce content clauses (e.g., “(I realized) how important …”), but it still doesn’t ask for information.

Where is the verb “to be”? Why is there no “is”?

Indonesian typically drops a copula with adjectives and nouns. Exclamations with betapa + ADJ-nya don’t need a verb.

Why is the adjective after the noun in langit mendung?

Indonesian places adjectives after nouns:

langit mendung = “overcast sky” You can optionally add yang for emphasis or clarity: langit yang mendung.

What part of speech is mendung?

Primarily an adjective meaning “overcast/cloud-laden.” It can also function as a noun in some contexts (e.g., mendung as “overcast conditions”), but here it modifies langit.

Is sebelum + noun (like sebelum petir) grammatical?

Yes. Sebelum can be followed by a noun phrase (“before lightning”) or a clause:

sebelum petir menyambar = “before lightning strikes”
sebelum ada petir = “before there is lightning” Using just sebelum petir is a succinct, idiomatic ellipsis.

Is petir the best word for “lightning”? How about kilat, halilintar, and what’s “thunder”?

petir: lightning (general; common and neutral).
kilat: the flash of lightning (the visual streak/flash).
halilintar: lightning; more literary/poetic.
guntur: thunder (the sound). So “before lightning” is sebelum petir; “before thunder” would be sebelum guntur.

Would natives more often say “before the rain” instead of “before lightning”?

Often, yes: sebelum hujan (“before it rains”) is very common. For maximum clarity about the lightning event, many would say sebelum petir menyambar (“before the lightning strikes”).

Can I replace betapa with something else for a similar exclamation?

Yes, common alternatives include:

Alangkah gelapnya …! (very natural)
Sungguh gelap …! / Begitu gelapnya …! Note: with begitu, you often still see -nya in this exclamative pattern.

How would this sound in everyday casual speech?

Something like:

Wah, gelap banget langitnya sebelum petir nyambar! Colloquial notes:
banget = very
nyambar = colloquial for menyambar (“strike”)
langitnya uses -nya as a definiteness/“the” marker: “the sky.”

How do I turn the exclamation into a neutral statement?

Langit mendung sangat gelap sebelum petir menyambar.
Langit mendung gelap sekali sebelum petir. Both mean it’s very dark before the lightning (strikes).

Is -nya in gelapnya the same as -nya in langitnya?

No, they’re different uses of the same clitic:

In gelapnya, it’s an exclamative/nominalizing particle with betapa.
In langitnya, it usually marks definiteness (“the sky”) or 3rd-person possession (“its”), depending on context.

Can I use berapa instead of betapa?

No. Berapa asks for quantity/number (“how many/how much?”). Betapa expresses degree in exclamations (“how + adjective!”) or introduces “how …” content clauses.