Learn Hardcore Indonesian: Hari ini kami belajar konsep kalimat aktif dan kalimat pasif dalam tatabahasa Indonesia. - Today we learn the concept of active sentences and passive sentences in Indonesian grammar.

Hari ini kami belajar konsep…
→ Puts extra emphasis on today (Today, we are learning…).
Kami belajar konsep… hari ini.
→ More neutral; just states when it happens.

Both are natural. Starting with a time expression like hari ini, kemarin, besok, etc. is very common in Indonesian and often sounds slightly more natural, especially in written or formal speech.

Why is kami used instead of kita? Aren’t they both “we”?

Both mean “we”, but:

kami = we excluding the listener
kita = we including the listener

So:

If a teacher is talking to students and means “we (teacher + students) are learning this today”, they would usually say:
Hari ini kita belajar…
If the speaker is talking to someone who is not part of the group that’s learning, then kami is correct:
Hari ini kami belajar… = “Today we (but not you) learned / are learning…”

The choice between kami and kita is about who is included, not grammar.

In English I’d say “Today we are learning…”. Why is it just belajar and not something like “sedang belajar” or “adalah belajar”?

Indonesian verbs do not need an extra verb like “to be” (am/is/are) to form continuous tenses.

Hari ini kami belajar…
can mean:
- Today we learn…
- Today we are learning…
- Today we will learn…
  The time word hari ini gives the context.

If you want to emphasize the ongoing action (like English “are learning right now”), you can say:

Hari ini kami sedang belajar konsep…

But saying adalah belajar is wrong; adalah is generally used to link nouns (like “X is Y”), not with verbs.

What’s the difference between belajar and mempelajari? Could I say Hari ini kami mempelajari konsep…?

Both are related to “learning/studying,” but there’s a nuance:

belajar
- basic verb “to learn, to study”
- can be intransitive: Saya belajar. (I’m studying.)
- can also take an object: Saya belajar bahasa Indonesia.
mempelajari
- more explicitly transitive, “to study (something) in depth”
- sounds a bit more formal or academic
- always takes an object: Saya mempelajari tatabahasa Indonesia.

In your sentence:

Hari ini kami belajar konsep kalimat aktif dan kalimat pasif…
Hari ini kami mempelajari konsep kalimat aktif dan kalimat pasif…

Both are grammatically correct.
mempelajari can sound slightly more serious or focused, like “we are studying the concept of active and passive sentences (in detail).”

Why is konsep used here? Could I just say kami belajar kalimat aktif dan kalimat pasif?

You can drop konsep, but the meaning shifts slightly:

Kami belajar konsep kalimat aktif dan kalimat pasif…
→ “We are learning the concept of active and passive sentences” (the theory/idea).
Kami belajar kalimat aktif dan kalimat pasif…
→ “We are learning active and passive sentences” (could sound more like practicing or using those sentences, not necessarily focusing on the abstract concept).

Both are understandable; konsep just makes it clear that you’re talking about the theory, not just examples.

Why is it kalimat aktif dan kalimat pasif, not kalimat-kalimat aktif dan pasif? How is plural shown here?

Indonesian usually doesn’t need to mark plural explicitly. kalimat here can mean:

“an active sentence and a passive sentence” or
“active sentences and passive sentences” (in general)

You can mark plural if you want to emphasize many:

kalimat-kalimat aktif dan pasif = “(multiple) active and passive sentences”

But in explanations of grammar, the unmarked singular often carries a generic, plural-like meaning (like English “The lion is a wild animal” = “lions are wild animals”). So:

kalimat aktif dan kalimat pasif is completely natural for “active and passive sentences.”

Could I say konsep kalimat aktif dan pasif instead of repeating kalimat twice?

Yes, you can:

konsep kalimat aktif dan kalimat pasif
konsep kalimat aktif dan pasif

Both are grammatical and natural. When you have:

X dan Y and X = Y (same noun), you can usually drop the second noun:
- bahasa Indonesia dan Inggris (instead of bahasa Indonesia dan bahasa Inggris)
- guru bahasa Indonesia dan Jepang

Repeating kalimat can make the structure clearer or slightly more formal, but it’s not required.

What exactly does dalam mean in dalam tatabahasa Indonesia? Could I use tentang instead?

Here, dalam literally means “in / within” and is often used in abstract, conceptual contexts:

dalam tatabahasa Indonesia
→ “in Indonesian grammar” / “within Indonesian grammar”

You can say:

konsep … dalam tatabahasa Indonesia
konsep … dalam bahasa Indonesia
konsep … dalam pelajaran bahasa Indonesia

tentang means “about”:

konsep tentang kalimat aktif dan pasif = “the concept about active and passive sentences”

So:

dalam tatabahasa Indonesia focuses on the field/framework (within the system of Indonesian grammar).
tentang kalimat aktif dan pasif focuses on the topic (about active and passive sentences).

Your original sentence uses dalam tatabahasa Indonesia to highlight that these concepts belong to the system of Indonesian grammar.

What’s the difference between tatabahasa Indonesia and bahasa Indonesia?

bahasa Indonesia = the Indonesian language in general (vocabulary, usage, speaking, etc.)
tatabahasa Indonesia = Indonesian grammar specifically (rules of structure, word order, verb forms, etc.)

So:

Hari ini kami belajar bahasa Indonesia.
→ Today we are learning Indonesian (the language in general).
Hari ini kami belajar tatabahasa Indonesia.
→ Today we are learning Indonesian grammar (a specific part of the language).

Why is it written as tatabahasa and not tata bahasa? Which one is correct?

Both forms exist:

tata bahasa = historically more common and very widely used
tatabahasa = also used, especially in some dictionaries or more formal/standardized spelling

Many native speakers still write tata bahasa as two words. In official contexts you might see either, but tata bahasa will always be understood and is very safe to use.

So you could also write:

Hari ini kami belajar konsep kalimat aktif dan kalimat pasif dalam tata bahasa Indonesia.

There are no words like “the” or “a” here. How do I know if it means “the concept” or “a concept”?

Indonesian does not have articles like the, a, or an. Nouns without extra markers are neutral:

konsep can mean:
- “a concept”
- “the concept”
- “concepts” (in a generic sense), depending on context.

In this sentence, the natural English translation would be “the concept of active and passive sentences”, because in a classroom grammar context, you’re usually talking about a specific, known concept.

If you need to be more precise in Indonesian, you use other words:

sebuah konsep = a concept (one concept)
konsep itu = that concept / the concept (already known from context)

Can I drop kami and just say Hari ini belajar konsep kalimat aktif dan kalimat pasif…?

Yes, you can drop the subject pronoun if it’s clear from context who is doing the action. Indonesian often omits pronouns when they are obvious.

Hari ini kami belajar…
→ explicit: we are the ones learning.
Hari ini belajar…
→ more context-dependent; could mean “(We/they/I) are learning today…”

In a classroom where everyone knows “we (students) are learning this today”, a teacher might casually write or say:

Hari ini belajar kalimat aktif dan pasif.

It’s still natural, but slightly less explicit. In textbooks or formal explanations, keeping kami (or kita) is clearer.