I spent two months saying "Apa kabar?" to literally everyone. Taxi drivers, friends, the guy at the warung, even my girlfriend's grandmother.
Nobody told me that in actual Indonesian conversations, nobody says "Apa kabar?" unless they're being hilariously formal or mocking textbook Indonesian.
That's the thing about politeness in Indonesian. Textbooks give you formal phrases. Real life gives you context. And the gap between them is where most learners get stuck.
The formal-informal split is simpler than you think
Indonesian has two main registers. Formal Indonesian (sometimes called bahasa baku) sounds like a news broadcast. Informal Indonesian (bahasa sehari-hari or bahasa gaul) sounds like actual humans talking.
The formal version is what you hear in government offices, news reports, and formal speeches. It uses complete sentences, proper pronouns, and sounds a bit stiff.
The informal version drops half the words, adds slang, and gets straight to the point.
Example:
Formal: "Saya ingin bertanya, apakah Anda sudah makan?"
Informal: "Udah makan?"
Both mean the same thing ("Have you eaten?"), but the first one sounds like you're interviewing someone for a job, and the second sounds like you're checking if your friend wants to grab lunch.
Pronouns are the biggest tell
In formal Indonesian, you use saya (I) and Anda (you). In informal Indonesian, almost nobody uses these.
Instead, you'll hear:
• aku/gue (I) – depending on region and level of informality
• kamu/lo (you) – again, region-dependent
• dia (he/she) – used in both registers but often dropped entirely in casual speech
I once called my friend's dad "lo" by accident because I'd been hanging out with university students all week. The look on his face taught me more about Indonesian politeness than any textbook ever could.
With elders or people you don't know well, you usually skip pronouns entirely or use titles: Pak (for men), Bu (for women), Mas/Mbak (for people roughly your age or slightly older).
The -kan and -lah particles vanish in real speech
Formal Indonesian loves these particles. "Duduklah" (please sit), "Makanlah" (please eat), "Jelaskan" (explain).
In casual Indonesian? Gone. Just "Duduk" or "Makan" or "Jelasin."
The -lah particle especially sounds weirdly formal unless you're giving a speech or being deliberately polite in a specific context (like addressing someone much older).
One exception: "Sudahlah" (never mind, forget it) is still common. But "Makanlah dulu" sounds like your grandmother talking.
When formal actually matters
You need formal Indonesian in specific situations:
• Job interviews
• Government offices
• Writing emails to professors or bosses
• Formal presentations
• Meeting someone's parents for the first time
Even then, Indonesians often code-switch mid-conversation once they feel comfortable. I've been in meetings that started with perfect formal Indonesian and ended with everyone using gue/lo and dropping particles.
The key is starting formal and waiting for the other person to shift registers first.
Regional differences complicate everything
Jakarta Indonesian (which is heavily influenced by Betawi dialect) sounds different from Yogyakarta Indonesian (which pulls from Javanese). Surabaya has its own flavor. Medan speaks differently.
In Jakarta, you'll hear "gue" and "lo" constantly. In Yogyakarta, "aku" and "kamu" are more common. Some regions use "saya" in casual contexts where others never would.
This isn't a bug in the language. It's just how it works. Indonesian is a young language (officially standardized in 1945) built on top of hundreds of regional languages, and those influences still shape how people talk.
If you're learning Indonesian, pick one region's informal style and stick with it. You'll sound more natural than someone trying to speak "neutral" Indonesian that nobody actually uses.
The mistakes I made (so you don't have to)
Using "Anda" in casual conversation. This makes you sound like a telemarketer or a language learning app. Just use names or titles.
Saying "Apa kabar?" to friends. They'll look at you funny and say "Baik" because it's technically correct, but it sounds bizarre. Just say "Apa kabar?" to people you haven't seen in months, or skip it entirely and go straight to "Mau ngapain?" (What are you up to?).
Over-using "maaf" (sorry). Indonesians do apologize, but not as reflexively as English speakers. Saying "maaf" before every request sounds overly formal. Just ask directly.
Sticking to formal Indonesian because it feels "safer." This keeps you at arm's length from actual fluency. You can communicate, but you'll always sound like a foreigner reading from a script.
How to actually learn this
Watch Indonesian YouTube. Not language learning channels—actual Indonesian YouTubers talking to their friends. You'll hear real informal Indonesian with all its dropped words and regional slang.
Use Bahasa.fun to practice conversations that actually reflect how people talk, not how textbooks think they talk.
Listen for register shifts in conversations. When does someone switch from formal to informal? That moment tells you everything about the social dynamics.
Don't stress about "correct" Indonesian. There's formal Indonesian (used in specific contexts), and there's the Indonesian people actually speak (which varies by region and situation). You need both.
The formal version gets you through official situations without embarrassing yourself. The informal version gets you friends, inside jokes, and actual fluency.
Start with formal when meeting someone new. Wait for them to drop the formality first. Then match their register.
That's it. That's the entire strategy.
Everything else is just vocabulary.