Learn Hardcore Malay: Kalau hujan lebat lagi dan halaman banjir, kami sudah tahu cara menyapu air dengan cepat. - If it rains heavily again and the yard floods, we already know how to sweep the water quickly.

hujan can mean both “rain” (noun) and “to rain” (verb).
So hujan lebat is understood as “(it) rains heavily” or “heavy rain”, without saying ia (“it”).

This is natural and standard. You almost never say ia hujan. You simply say:

Hari ini hujan. – It’s raining today.
Tadi malam hujan lebat. – It rained heavily last night.

So kalau hujan lebat lagi is a normal way to say “if it rains heavily again”; the “it” is just understood from context, not expressed.

What exactly does kalau mean here? How is it different from jika, bila, or apabila?

kalau here means “if”. Common conditional words:

kalau – “if / when (if-type)”; very common and informal–neutral.
jika – “if”; more formal, often in writing, rules, official speech.
bila – “when” in many dialects; in some areas it can also mean “if”.
apabila – “when / whenever / if”; more formal or written style.

In this sentence, you could also say:

Jika hujan lebat lagi dan halaman banjir, … (more formal)
Apabila hujan lebat lagi dan halaman banjir, … (formal, written)

In everyday conversation, kalau is the most natural choice.

What does lagi add in kalau hujan lebat lagi? Does it mean “again”, “more”, or “still”?

lagi is flexible; here it means “again”.

Possible meanings of lagi depend on context:

again
- kalau hujan lebat lagi – if it rains heavily again
more / another
- saya mahu satu lagi – I want one more.
still
- dia masih tidur lagi – he is still sleeping.

Because the situation is about rain happening once more in the future, lagi is understood as “again”: if it’s heavy rain again…

In dan halaman banjir, why is it just halaman banjir and not something like halaman itu banjir or halaman dibanjiri?

Here halaman is the subject and banjir is a stative verb / adjective-like verb meaning “(to be) flooded”.

halaman banjir literally: “the yard floods / the yard is flooded”.
Malay often uses bare verbs in a stative sense, where English uses “is + adjective/past participle”.

You could also see:

halaman itu banjir – “that yard is flooded” (more specific).
halaman dibanjiri air – “the yard is flooded (lit. flooded by water)” – more formal, emphasising the action of being flooded.
halaman kebanjiran – “the yard gets flooded” (has a “was hit by flooding” nuance).

In everyday speech, halaman banjir is perfectly natural and concise to express “the yard floods / is flooded.”

The meaning is future (“if it rains again…”), so why does the main clause use sudah tahu (“already know”) instead of some future form?

Malay focuses more on aspect (completed / already) than strict tense.

sudah = already / have (done).
kami sudah tahu = “we already know” (now).

The structure is:

Condition (future): kalau hujan lebat lagi dan halaman banjir – if it rains heavily again and the yard floods
Existing fact (present, already true): kami sudah tahu cara menyapu air dengan cepat – we already know how to sweep the water quickly.

So the sentence means: whenever that situation happens again in the future, we already have the knowledge now to handle it quickly. The future-ness comes from the kalau-clause, not from the verb form in the main clause.

Could we say kami akan tahu cara menyapu air instead of kami sudah tahu? What would change?

Yes, but it changes the meaning.

kami sudah tahu cara menyapu air
= we already know how to sweep the water (now).
kami akan tahu cara menyapu air
= we will know how to sweep the water (only in the future, as a result).

So:

Original: If it rains heavily again and the yard floods, we already know how to sweep the water quickly.
→ Knowledge is present now, based on past experience.
With akan: Kalau hujan lebat lagi dan halaman banjir, kami akan tahu cara menyapu air dengan cepat.
→ Implies that when that situation happens, then we will know (e.g. we will figure it out at that time).

In the given sentence, sudah is chosen to stress existing, already-acquired knowledge.

Why is it kami and not kita? Don’t they both mean “we”?

Both mean “we”, but they differ in inclusiveness:

kami = we (not including you) – exclusive.
kita = we (including you) – inclusive.

So:

kami sudah tahu… – we (some group that excludes the listener) already know…
kita sudah tahu… – we (including you, the person I’m talking to) already know…

The choice tells you whether the listener is part of the group with that knowledge.
In real use:

Talking among family members about the family’s yard, you might say kita.
Talking to an outsider about your own household, you might say kami.

The sentence by itself just states exclusive we (kami); context decides if that’s appropriate.

In cara menyapu air, why is it just cara + verb? Could we also say cara untuk menyapu air?

Both are possible, but cara + verb is very common and natural.

cara menyapu air – literally “way (of) sweeping water”, i.e. how to sweep the water.
cara untuk menyapu air – “way to sweep water” (with untuk = for / to). Slightly more explicit or formal, but still normal.

Usage patterns:

After cara, Malay often just uses a bare verb:
- cara memasak nasi – how to cook rice
- cara mengelap lantai – how to wipe the floor

Adding untuk is optional and can sound a bit more formal or explanatory, but there’s no big difference in basic meaning here.

What does menyapu air literally mean? Can menyapu be used with things other than floors?

menyapu literally means “to sweep” (with a broom or similar motion).

menyapu lantai – sweep the floor
menyapu halaman – sweep the yard

menyapu air is natural Malay meaning “to sweep (push away) water”, typically with a broom, squeegee, or similar tool to move the water off the floor/yard.

So cara menyapu air is something like “the way of sweeping out the water”, i.e. techniques for removing the water quickly.

Why is the adverb dengan cepat used? Could we say cepat-cepat or secara cepat instead?

All are possible, but they differ in style and nuance.

dengan cepat – literally “with quickness”, i.e. “quickly”.
- Standard, neutral, and very common.
cepat-cepat – reduplication adds a sense of urgency / doing it quickly and immediately.
- More colloquial, can feel a bit more emotional: “very quickly / hurry up and do it”.
secara cepat – more formal, more like “in a fast manner”.
- Common in formal writing / technical or academic style.

In this everyday context, dengan cepat is the most natural and neutral way to say “quickly”.

Can the order of the clauses be reversed, like in English: “We already know how to sweep the water quickly if…”?

Yes. Malay allows both orders:

Kalau hujan lebat lagi dan halaman banjir, kami sudah tahu cara menyapu air dengan cepat.
Kami sudah tahu cara menyapu air dengan cepat kalau hujan lebat lagi dan halaman banjir.

Both are grammatical.
Differences:

Starting with kalau… puts more focus on the condition.
Starting with kami sudah tahu… puts more focus on what we already know.

In speech, people often put kalau at the beginning, but the reversed order is also common and acceptable.