Learn Hardcore Indonesian: Guru kami aktif di perpustakaan. - Our teacher is active in the library.

Indonesian usually drops “to be” before adjectives. So Guru kami aktif literally reads “Our teacher active,” which means “Our teacher is active.” You don’t add adalah before an adjective. Use adalah mainly when the predicate is a noun: Guru kami adalah koordinator perpustakaan (Our teacher is the library coordinator).

Does Guru kami refer to one teacher or multiple teachers?

It can be either, depending on context. Indonesian doesn’t mark plural by default. If you need to be explicit:

Plural: guru-guru kami or para guru kami
Definitely one specific teacher: guru kami itu
“One of our teachers”: seorang guru kami

What’s the difference between kami and kita?

kami = “we/our” excluding the listener.
kita = “we/our” including the listener. So guru kami = “our teacher (not yours),” while guru kita = “our teacher (yours and ours).” Choose based on inclusivity.

Why is the pronoun after the noun (Guru kami) and not before (like “our teacher”)?

In Indonesian, possessors follow the noun they possess. Guru kami = “our teacher(s).” If you put the pronoun first, kami guru means “we are teachers,” which is a sentence, not a noun phrase.

Does di mean “in” or “at” in di perpustakaan?

Both. di marks a location in a general sense and can map to “in/at/on” depending on English context. For directions, use ke (to) and dari (from): ke perpustakaan, dari perpustakaan.

When would I say di dalam perpustakaan instead of di perpustakaan?

Use di dalam to emphasize being inside the physical interior: Dia belajar di dalam perpustakaan (specifically inside). Di perpustakaan already usually implies “in/at the library” and is fine in most contexts.

Can I use pada here instead of di?

Not here. pada is more formal/abstract and isn’t normally used for physical locations. Say aktif di perpustakaan, not aktif pada perpustakaan. If you mean activity/field rather than place, use:

aktif dalam kegiatan perpustakaan (active in library activities)
aktif di bidang perpustakaan (active in the field of librarianship)

What nuance does aktif di have compared to bekerja di or sering di?

aktif di implies involvement/participation (committees, programs, events).
bekerja di means “works at” (employment).
sering di means “is often at” (frequency of being there). Example: Guru kami aktif di perpustakaan, but not necessarily employed there.

Is perpustakaan “the library” or “a library”?

Indonesian has no articles. perpustakaan can be “the” or “a” library depending on context. To specify a particular one, add a determiner or modifier:

perpustakaan itu (that/the library)
perpustakaan sekolah (the school library)

How do I say “Our teachers are active in the library”?

Use a plural marker:

Para guru kami aktif di perpustakaan.
Guru-guru kami aktif di perpustakaan.

How do I say “Our teacher who is active in the library …” to start a relative clause?

Use yang: Guru kami yang aktif di perpustakaan …
Example: Guru kami yang aktif di perpustakaan sedang menyusun katalog.

Is Guru kami adalah aktif di perpustakaan acceptable?

No. Don’t put adalah before an adjective. Say Guru kami aktif di perpustakaan. Use adalah when the predicate is a noun: Guru kami adalah pengelola perpustakaan.

What part of speech is aktif? How can I modify it?

aktif is an adjective. Common intensifiers:

sangat aktif (very active)
cukup aktif (fairly active)
aktif sekali (very active) Related forms: keaktifan (activeness, noun), mengaktifkan (to activate, verb—technical).

Pronunciation tips?

guru: “goo-roo” (u like “oo” in “food”)
kami: “kah-mee” (a like “father”)
aktif: “ak-teef” (final f is pronounced)
perpustakaan: syllables: per-pus-ta-ka-an (stress is fairly even)

How do I say “my teacher,” “your teacher,” “his/her teacher”?

My teacher: guru saya or guruku (colloquial, with -ku)
Your teacher: guru kamu/Anda or gurumu
His/her teacher: gurunya For “our,” there’s no suffix form; use guru kami/kita.

How can I emphasize “It’s our teacher who is active in the library”?

Use a cleft with -lah and yang: Guru kamilah yang aktif di perpustakaan.

Can I say guru aktif to mean “an active teacher”? How is that different from the sentence?

Yes. guru aktif is an attributive noun phrase (“an active teacher”). Your sentence Guru kami aktif … uses aktif as the predicate (“Our teacher is active …”). If you need “our active teacher,” say guru kami yang aktif.

What does perpustakaan literally come from?

It’s a derivation of pustaka (book/literature) with the circumfix per- … -an, forming a place noun: perpustakaan = “library.”