Learn Hardcore Indonesian: Wi‑Fi di perpustakaan stabil pagi ini. - The Wi‑Fi in the library is stable this morning.

Indonesian doesn’t require a copula with adjectives. Wi‑Fi di perpustakaan stabil already means “The Wi‑Fi at the library is stable.” Use adalah mainly when the predicate is a noun or for emphasis.

Correct: Wi‑Fi di perpustakaan stabil.
Unnatural: Wi‑Fi di perpustakaan adalah stabil.
With a noun: Wi‑Fi di perpustakaan adalah jaringan nirkabel.

What does di mean, and how is it different from ke?

di marks location (“at/in/on”), while ke marks movement (“to/toward”).

di perpustakaan = at the library
ke perpustakaan = to the library

Should di be written together like diperpustakaan?

No. As a preposition meaning “at/in,” di is written separately: di perpustakaan. It’s only attached when it’s the passive prefix on a verb (e.g., ditulis “written”).

What exactly does pagi ini mean? How is it different from tadi pagi or pada pagi ini?

pagi ini = “this morning” (today’s morning; neutral, often still relevant now).
tadi pagi = “earlier this morning” (clearly past).
pada pagi ini = more formal/stylistic; everyday speech usually just uses pagi ini.

Can I move the time or place around?

Yes. Time and place adjuncts are flexible:

Pagi ini, Wi‑Fi di perpustakaan stabil.
Wi‑Fi di perpustakaan stabil pagi ini. (your version)
Wi‑Fi di perpustakaan pagi ini stabil.
Wi‑Fi stabil di perpustakaan pagi ini. If you front the time, adding a comma (Pagi ini, …) is common but not mandatory.

How do I say “the library’s Wi‑Fi” instead of “Wi‑Fi at the library”?

Use a noun–noun compound:

Wi‑Fi perpustakaan / jaringan Wi‑Fi perpustakaan To make it specific: Wi‑Fi perpustakaan itu stabil pagi ini.

How can I make “the library” specific, like “this/that library”?

Add a demonstrative after the noun:

di perpustakaan ini = at this library
di perpustakaan itu = at that/the library (specific) You can also use -nya when context already identifies it: di perpustakaannya.

Is stabil the right word? What are common alternatives?

stabil emphasizes consistency (not dropping out), not necessarily speed. Alternatives:

lancar = smooth/without interruptions
cepat/kencang = fast
tidak putus-putus = not cutting out Example: Wi‑Fi di perpustakaan lancar pagi ini.

How do I intensify or soften the adjective?

Very: sangat stabil (formal/neutral), stabil sekali, or colloquial stabil banget
Quite/fairly: cukup stabil Example: Wi‑Fi di perpustakaan sangat stabil pagi ini.

How do I negate it or turn it into a question?

Negation: tidak before the adjective
- Wi‑Fi di perpustakaan tidak stabil pagi ini.
Yes/no question:
- Intonation: Wi‑Fi di perpustakaan stabil pagi ini?
- Formal: Apakah Wi‑Fi di perpustakaan stabil pagi ini?
- Colloquial: Apa Wi‑Fi di perpustakaan stabil pagi ini? Tag-style: …, ya? for confirmation.

If I mean past (“was stable this morning”), do I need a past tense marker?

Indonesian has no tense inflection. Use time words:

Tadi pagi, Wi‑Fi di perpustakaan stabil.
Wi‑Fi di perpustakaan tadi pagi stabil.

Why is ini after pagi? Can it come before?

Demonstratives follow the noun/time word: pagi ini, hari ini, minggu ini. You don’t say ini pagi for “this morning.”

Can I say sedang stabil?

Usually you don’t use sedang with adjectives like stabil in everyday speech. Just say stabil. In technical/formal contexts describing a process/state you might see it (e.g., kondisi sedang stabil), but it’s not needed here.

Is perpustakaan singular or plural?

Nouns aren’t marked for number. perpustakaan can mean “library/libraries” depending on context. To make it clearly plural, use reduplication or a quantifier:

perpustakaan-perpustakaan, banyak perpustakaan

What does perpustakaan literally come from?

Root pustaka (“book”; from Sanskrit) + affixes per- … -an (often forms “place/collection” nouns) → perpustakaan = “place of books” = library.

Should I say di dalam perpustakaan to mean “inside the library”?

di perpustakaan already means “at/in the library.” Use di dalam perpustakaan only if you want to stress “inside the interior of the library.”

Any tips on pronunciation?

perpustakaan: pehr-PUS-ta-ka-an (five syllables; the e in per- is a schwa; there’s a slight break between ka and an)
stabil: STA-bil (short, clear vowels)
pagi ini: PA-gee EE-nee (hard g) Stress in Indonesian is light, often on the penultimate syllable; don’t overemphasize it.

What about capitalization and spelling of Wi‑Fi?

Standard dictionaries write Wi‑Fi (capital W, hyphen). You’ll also see wifi/WiFi informally. perpustakaan is lowercase unless it’s part of a proper name (e.g., Perpustakaan Nasional).