Learn Hardcore Indonesian: Keluarga kami saling mendukung ketika ada masalah. - Our family supports each other when there is a problem.

Kami keluarga is not the normal way to say our family.
Kami sekeluarga does exist, but it means something like we, as a whole family (used as a subject, e.g. Kami sekeluarga akan pindah.).

What does saling add to the meaning of mendukung?

mendukung alone means to support (someone/something).

saling means each other / mutually / one another.
Putting them together:

mendukung = support
saling mendukung = support each other / mutually support

So:

Keluarga kami mendukung.
= Our family supports (someone/something) — not clear whom.
Keluarga kami saling mendukung.
= Family members support one another.

saling is a very common way to express reciprocal actions:

saling mencintai = love each other
saling membantu = help each other
saling menghormati = respect each other

Is saling mendukung satu sama lain correct, or is that redundant?

You might hear or read:

saling mendukung satu sama lain
(support each other one another)

Grammatically it’s fine, and people do say it, especially in speech or emotional writing.

However, it is technically redundant because saling already means each other and satu sama lain also means one another. For clear, natural Indonesian, saling mendukung by itself is usually enough.

How is mendukung formed, and is there a reason it’s not just dukung?

The base word is dukung (support).
Indonesian often adds prefixes to turn roots into verbs:

meN- + dukung → mendukung

The meN- prefix (here realized as men-) usually forms an active verb:

tulis → menulis (to write)
bantu → membantu (to help)
dukung → mendukung (to support)

You can see dukung by itself in some patterns (e.g. dukungan = support [noun], pendukung = supporter), but in a normal active sentence with a subject, mendukung is the natural choice.

How do we know the tense? Does it mean “support each other”, “supported each other”, or “will support each other”?

Indonesian verbs don’t change form for tense. mendukung can cover:

present: support / are supporting
past: supported
future: will support
habitual: (always) support

Here, Keluarga kami saling mendukung ketika ada masalah is a general, habitual statement:

Our family (always/typically) supports each other whenever there is a problem.

If you need to be specific, you add time words:

dulu = formerly, in the past
sekarang = now
nanti = later
akan = will (future marker)

Example: Dulu keluarga kami saling mendukung ketika ada masalah. = In the past, our family supported each other when there was a problem.

What is the difference between ketika, kalau, and jika here?

All three can show a clause like “when/if there is a problem”, but with slightly different feels:

ketika ada masalah
Literally when there is a problem (time-based, fairly neutral).
Sounds good in both spoken and written Indonesian.
kalau ada masalah
Often if/when there is a problem (more conditional, very common in speech).
This version sounds slightly more informal/colloquial.
jika ada masalah
If there is a problem (more formal, used in writing, instructions, formal speech).

In this sentence, ketika ada masalah sounds like a general “whenever there’s a problem” and is natural and neutral.

Why is it ketika ada masalah instead of something like ketika kami punya masalah?

Both are possible, but they have slightly different nuances:

ketika ada masalah
= when there is a problem (in the family)
This is impersonal and general. It focuses on the existence of a problem.
ketika kami punya masalah
= when we have a problem
More direct, emphasizing we as the ones experiencing the problem.

The original sentence sounds like a general rule about the family: > Whenever a problem arises, our family members support each other.

If you say ketika kami punya masalah, you are highlighting our personal experience of the problem.

Does masalah mean one problem or many problems? Where is the plural?

masalah literally is singular (a problem), but Indonesian often uses the same form for singular and plural. Context tells you which is meant.

So ada masalah can mean:

there is a problem
there are problems

If you really want to stress plurality, you can say:

masalah-masalah (reduplication for plural)
berbagai masalah = various problems
banyak masalah = many problems

In everyday speech, masalah alone is normally enough, just as in ada masalah in this sentence.

Can we move ketika ada masalah to the beginning of the sentence?

Yes. Indonesian word order is quite flexible for time/condition clauses. You can say:

Keluarga kami saling mendukung ketika ada masalah.
Ketika ada masalah, keluarga kami saling mendukung.

Both are correct and natural.
Putting ketika ada masalah first slightly emphasizes the situation (the problems) before mentioning what the family does.

Can we drop kami and just say Keluarga saling mendukung ketika ada masalah?

Yes, grammatically you can say:

Keluarga saling mendukung ketika ada masalah.

This would mean The family members support each other when there is a problem, but:

It no longer clearly shows whose family it is.
It sounds more like a general statement about “the family” already known from context, or about families in general.

If you want to say our (not your) family, keeping keluarga kami is clearer and more natural.

What level of formality does this sentence have? Is it polite, casual, or formal?

Keluarga kami saling mendukung ketika ada masalah. is:

grammatically standard
neutral in tone
suitable for spoken and written contexts

You could use it:

in everyday conversation
in a school essay
in a presentation
in a written description of your family

To make it even more formal, you might change other parts of a longer text, but this sentence on its own is already appropriately neutral and polite.