Learn Hardcore Indonesian: Hujan deras, jadi halaman belakang basah. - It is raining heavily, so the backyard is wet.

Indonesian often allows dropping or hiding the subject when it’s clear from context. Here Hujan deras literally means “heavy rain,” but as a standalone clause it implies “It’s raining heavily.” The full idea “It rained heavily” is understood without an explicit itu or pronoun.

What part of speech is deras in Hujan deras?

In this phrase deras is an adjective modifying the noun hujan (“rain”), so Hujan deras = “heavy rain.” Note that deras can also act as an adverb in sentences like “Hujan turun deras” (“The rain falls heavily”).

Why isn’t there a copula like “is” in halaman belakang basah?

Indonesian does not use a separate “to be” verb when the predicate is an adjective. You simply state Subject + Adjective. So halaman belakang basah is “(the) backyard wet,” equivalent to “the backyard is wet.”

Why are there no articles such as “the” or “a” in this sentence?

Indonesian does not have definite or indefinite articles like the or a/an. Context and word order tell you whether you’re talking about something specific or general.

What does jadi mean here? Is it the same as “to become”?

In Hujan deras, jadi halaman belakang basah the word jadi works as a conjunction meaning “so” or “therefore.” It connects cause and effect. Separately, jadi can also be a verb meaning “to become,” but that sense isn’t used here.

Is this sentence formal or informal?

It’s colloquial/informal. A more formal version would use a full conjunction like karena or sehingga, and perhaps the verb menjadi:
Karena hujan deras, halaman belakang menjadi basah.

Why isn’t there a preposition di before halaman belakang?

Here halaman belakang is the grammatical subject (the thing that is wet), not a location phrase. If you wanted to say “wet in the backyard,” you’d use di halaman belakang as an adverbial. But since you’re describing the backyard itself being wet, no di is needed.

Could I replace jadi with sehingga, makanya, or karena?

Yes. All these words can link cause and effect, though they differ in formality and nuance:

Karena hujan deras, halaman belakang basah. (Because…)
Hujan deras sehingga halaman belakang basah. (So that…)
Hujan deras, makanya halaman belakang basah. (That’s why…)

Why is the word order halaman belakang basah instead of basah halaman belakang?

Standard Indonesian follows a Subject-Predicate order. halaman belakang (subject) comes first, followed by basah (predicate adjective). Reversing them would break the usual syntax.

How would you turn this into a question to confirm the result?

You could ask:
“Apakah halaman belakang basah karena hujan deras?”
This literally means “Is the backyard wet because of heavy rain?”