Learn Hardcore Indonesian: Dia menjelaskan bahwa kesalahan pertama bisa saja menjadi pelajaran paling penting. - He/She explains that the first mistake can easily become the most important lesson.

Main clause: Dia menjelaskan – He/She explained
Subordinate clause introduced by bahwa – bahwa kesalahan pertama bisa saja menjadi pelajaran paling penting – that the first mistake might become the most important lesson.

So overall: “He/She explained that the first mistake might (even) become the most important lesson.”

Does dia mean “he” or “she”? How do I know the gender?

Dia is a gender-neutral third person singular pronoun in Indonesian. It can mean:

he
she

Indonesian usually doesn’t mark gender in pronouns. To know whether it’s “he” or “she,” you’d need context (who they were talking about earlier). If the context is unclear, you can safely translate it as “he/she” or just pick one according to the situation.

Why is bahwa used here? Is it necessary?

Bahwa is a conjunction that introduces a “that”-clause in English, like:

Dia menjelaskan bahwa … → He/She explained that …

It is:

Formal / neutral in style.
Often optional in spoken Indonesian.

You could also say:

Dia menjelaskan kesalahan pertama bisa saja menjadi pelajaran paling penting.

This is still correct and more natural in everyday speech. In writing, especially formal writing, bahwa is quite common.

Can I replace bahwa with kalau here?

In informal spoken Indonesian, people very often use kalau instead of bahwa in this type of “that-clause”:

Dia menjelaskan kalau kesalahan pertama bisa saja menjadi pelajaran paling penting.

This is natural in conversation.

However:

bahwa → more formal / written.
kalau → more informal / conversational, and it also usually means “if/when” in other contexts.

For careful writing or exams, bahwa is the safer choice here.

What is the nuance of bisa saja compared to just bisa?

Both involve possibility, but the nuance differs:

bisa = can / could / is able to / might
- kesalahan pertama bisa menjadi pelajaran penting
  → the first mistake can/might become an important lesson.
bisa saja adds:
- a sense of “might very well”, “could easily”, or
- “it wouldn’t be surprising if …”

So:

kesalahan pertama bisa saja menjadi pelajaran paling penting
≈ the first mistake might very well become the most important lesson / could easily become the most important lesson.

Saja here softens or slightly emphasizes the possibility, often sounding more natural and idiomatic.

Where does saja go? Could I say kesalahan pertama saja bisa menjadi …?

Word order affects nuance:

In the sentence given:
kesalahan pertama bisa saja menjadi pelajaran paling penting
→ bisa saja modifies the possibility of becoming the lesson.

If you say:

kesalahan pertama saja bisa menjadi pelajaran paling penting

Then saja is closer to kesalahan pertama, which can suggest:

“Even the first mistake can become the most important lesson,”
emphasizing “the first mistake (and not others)” or “just the first one.”

So both are grammatically possible, but bisa saja is a fixed, common chunk meaning “might very well / could easily,” and that’s what’s used in the original sentence.

Why use menjadi? Could I just say kesalahan pertama adalah pelajaran paling penting?

Menjadi means “to become” and implies a change over time:

bisa saja menjadi pelajaran paling penting
→ might become the most important lesson (in the future / as a result).

If you say:

kesalahan pertama adalah pelajaran paling penting
→ the first mistake is the most important lesson.

This sounds more like a timeless statement rather than something that might develop into a lesson. In this context, menjadi fits better because a mistake turns into a lesson after you learn from it.

Does kesalahan pertama mean “first mistake ever,” or just “the first mistake in a series”?

Kesalahan pertama literally means “the first mistake” and usually refers to:

the first mistake in a particular sequence or situation being discussed.

It doesn’t automatically mean “first mistake in your whole life”; that would need extra context like:

kesalahan pertama dalam hidupnya – the first mistake in his/her life

In most contexts, readers will understand kesalahan pertama as “the first mistake (in that context)”.

What does pelajaran mean here? Is it a school “lesson”?

Pelajaran can mean:

A school lesson / subject
- pelajaran matematika – math lesson / math subject
A life lesson / something you learn from experience
- kesalahan itu menjadi pelajaran bagi saya – that mistake became a lesson for me.

In your sentence, it clearly has the second meaning:
“the most important (life) lesson” learned from making a mistake, not a school class.

How does paling penting work? Is this the normal way to say “most important”?

Yes, paling is the common way to form the superlative in Indonesian:

penting – important
lebih penting – more important
paling penting – most important

So:

pelajaran paling penting – the most important lesson

Compared with:

pelajaran sangat penting – a very important lesson (not necessarily the most important; just very important)

Paling is neutral and widely used in both spoken and written Indonesian.

How do we know the tense? Why is it translated as “explained,” not “explains” or “is explaining”?

Indonesian verbs usually do not change form for tense. Menjelaskan stays the same for:

Dia menjelaskan …
→ He/She explains …
→ He/She explained …
→ He/She is explaining …

Which English tense to use depends entirely on context:

In a narrative about something that happened, you’d naturally translate it as “explained” (past).
In a general statement (e.g., reporting what someone always says), you might use “explains.”

Without context, “explained” is just one reasonable choice.

Could I use other verbs instead of menjelaskan, like mengatakan or bilang?

Yes, but there are differences in tone:

menjelaskan – to explain
- More formal / neutral
- Suggests giving a clearer, more detailed explanation.
mengatakan – to say / to state
- More formal than bilang, often written.
- Focuses on saying, not necessarily clarifying.
bilang – to say (informal, spoken)
- Very common in daily conversation.
- You might hear: Dia bilang kalau kesalahan pertama bisa saja menjadi pelajaran paling penting.

So in your sentence, menjelaskan is appropriate because it matches the idea of explaining (making something clear), and it sounds reasonably formal/neutral.