Learn Hardcore Indonesian: Dia belajar bahasa Inggris di perpustakaan.

ia – also “he/she”, but a bit more literary/formal, more common in writing.
beliau – respectful “he/she” for someone you honor (teachers, elders, officials).
mereka – “they” (plural), not dia.

How do we know the tense of belajar in this sentence? Does it mean “is studying”, “studied”, or “will study”?

The verb belajar itself has no tense. Indonesian verbs don’t change form for past/present/future.

Dia belajar bahasa Inggris di perpustakaan can mean:

He/She studies English at the library (habitual / general statement)
He/She is studying English at the library (right now / current activity)
He/She studied English at the library (past, if the context is past)
Less commonly, He/She will study English at the library (if a future time is given by context).

To specify time, you add time words:

sedang → ongoing now:
Dia sedang belajar bahasa Inggris di perpustakaan. = He/She is studying English at the library (right now).
sudah → already (past):
Dia sudah belajar bahasa Inggris di perpustakaan. = He/She has already studied English at the library.
akan → will (future):
Dia akan belajar bahasa Inggris di perpustakaan. = He/She will study English at the library.

Why is there no word for “the” or “a” in Indonesian, like “at the library”?

Indonesian generally has no articles like a, an, the.

Perpustakaan by itself can be translated as a library, the library, or just library, depending on context.
So di perpustakaan can be:
- at the library
- in a library
- in the library

If you need to be very specific, you can add more detail:

di perpustakaan itu – at that library / in the library (that we both know about)
di perpustakaan sekolah – at the school library

What is the exact role of belajar here? Is it transitive (taking an object) or intransitive?

In this sentence, belajar is transitive, because it takes a direct object: bahasa Inggris.

Dia belajar.
= He/She studies / He/She is learning. (no object → more general)
Dia belajar bahasa Inggris.
= He/She studies / is learning English. (now the object is specified)

You can also place di perpustakaan with or without the object:

Dia belajar di perpustakaan. – He/She studies at the library. (what subject is not specified)
Dia belajar bahasa Inggris di perpustakaan. – He/She studies English at the library. (subject specified)

There is also mempelajari, which is more formal and clearly transitive:

Dia mempelajari bahasa Inggris. – He/She studies (the subject of) English.
In everyday speech, belajar is more common.

What does bahasa Inggris literally mean? Why do we need the word bahasa?

Bahasa Inggris literally means English language.

bahasa = language
Inggris = England / English (related to England)

So:

bahasa Inggris = English (language)
bahasa Indonesia = Indonesian (language)
bahasa Jepang = Japanese (language)

In English we usually drop “language” and just say English, but in Indonesian you almost always say bahasa + [language name] when talking about languages.

Why is bahasa lowercase but Inggris capitalized?

In standard Indonesian spelling:

Names of languages and countries are capitalized:
Inggris, Indonesia, Jepang, Prancis, etc.
Common nouns like bahasa (language) are not capitalized unless they start a sentence.

So:

bahasa Inggris – correct (language name, common + proper noun)
Bahasa Inggris – sometimes seen, especially in course titles or logos, but the fully standard form in running text is bahasa Inggris.
Bahasa Indonesia is widely seen in official contexts, but style guides now often prefer bahasa Indonesia unless it starts a sentence.

What does perpustakaan mean exactly? Is there any clue in the word itself?

Perpustakaan means library.

It is formed from:

pustaka – an older word meaning book / manuscript / literature
the prefix per- and suffix -an, which often form nouns related to places or collections.

So perpustakaan is literally something like a place of books → library.

Everyday meaning:

perpustakaan: a place where books (and other materials) are stored, that you can read or borrow – library.

What is the function of di in di perpustakaan? How is it different from ke?

Di is a preposition meaning at / in / on (location).

di perpustakaan = at the library / in the library

Ke is a preposition meaning to (direction or movement).

Compare:

Dia belajar bahasa Inggris di perpustakaan.
= He/She studies English at the library. (location)
Dia pergi ke perpustakaan.
= He/She goes to the library. (movement toward)

Important spelling:

di as a preposition is always written separately: di perpustakaan, di rumah.
There is also di- as a prefix for passive verbs (e.g. dibaca, ditulis), which is attached to the verb. That’s a different di.

Is the word order fixed? Can I move di perpustakaan to another position?

The basic word order in Indonesian is S–V–O–(Adverbials), similar to English:

Dia (S) belajar (V) bahasa Inggris (O) di perpustakaan (adverbial phrase of place).

You can move the place phrase for emphasis or style:

Dia belajar bahasa Inggris di perpustakaan.
Neutral, most common.
Di perpustakaan, dia belajar bahasa Inggris.
Emphasizes at the library; natural especially in writing or storytelling.
Dia di perpustakaan belajar bahasa Inggris.
Possible, but less common; can sound a bit marked or spoken/storytelling style, emphasizing that it’s at the library that he/she studies English.

For learners, the safest and most neutral is: Dia belajar bahasa Inggris di perpustakaan.

Can I drop the subject Dia and just say Belajar bahasa Inggris di perpustakaan?

In a full, normal sentence, you usually keep the subject:

Dia belajar bahasa Inggris di perpustakaan. – standard sentence.

However, subject dropping can happen:

in instructions, notes, headlines, or very informal speech where context is very clear.

Examples:

A sign or instruction: Belajar bahasa Inggris di perpustakaan.
Could mean: Study English in the library. (addressing “you” in general)
In conversation, replying to a question:
- A: Dia lagi apa? – What is he/she doing?
- B: Belajar bahasa Inggris di perpustakaan.
  (Drop dia because it’s obvious from the question.)

But as a learner, when making normal sentences, it’s better to include the subject: Dia belajar …

Is this sentence formal or informal? Is dia polite enough?

The sentence Dia belajar bahasa Inggris di perpustakaan is neutral in style.

Dia is:
- OK in almost all contexts: daily conversation, neutral writing, classrooms, etc.
- Not rude; it’s standard.
For more respectful reference to an older or important person, you might use:
- beliau – he/she (honorific)
  Example: Beliau belajar bahasa Inggris di perpustakaan.
  (Talking respectfully about a teacher, professor, official, etc.)

The rest of the sentence (belajar bahasa Inggris di perpustakaan) is also neutral and fine in both spoken and written Indonesian.

How is this sentence pronounced? Where is the stress?

A simple pronunciation guide (using rough English-like spelling):

Dia → DEE‑ah
(2 syllables: di‑a, both vowels clear)
belajar → buh‑LAH‑jar
(3 syllables: be‑la‑jar, stress usually on la)
bahasa → ba‑HAH‑sa
(3 syllables: ba‑ha‑sa, stress usually on ha)
Inggris → ING‑gris
(2 syllables: ing‑gris, stress on ing; roll the r lightly)
di → dee
perpustakaan → per‑pus‑ta‑KA‑an
(5 syllables: per‑pus‑ta‑ka‑an, common stress on ka)

Overall:
Dia belajar bahasa Inggris di perpustakaan.
≈ DEE‑ah buh‑LAH‑jar ba‑HAH‑sa ING‑gris dee per‑pus‑ta‑KA‑an

Does dia ever mean “they”? How do you say “They study English at the library”?

Dia is always singular (he/she).

To say they, you use mereka.

Dia belajar bahasa Inggris di perpustakaan.
= He/She studies English at the library.
Mereka belajar bahasa Inggris di perpustakaan.
= They study English at the library.

Note:

mereka does not distinguish gender, just like dia, but it clearly indicates plural.