Learn Hardcore Indonesian: Remaja itu menulis puisi tentang kakek dan nenek di buku harian. - That teenager writes a poem about grandpa and grandma in the diary.

Remaja itu literally: that teenager / the teenager.
In Indonesian, demonstratives like itu and ini normally come after the noun:
- buku itu = that/the book
- orang ini = this/the person

So remaja itu is the natural order; putting itu remaja would be wrong in standard Indonesian.

Does remaja tell us if the teenager is male or female?

No. Remaja is gender‑neutral. It just means teenager / adolescent.

If you need to specify gender, you add another word:

remaja laki-laki = male teenager
remaja perempuan = female teenager

But in most contexts, remaja alone is enough, and listeners infer gender from context if it matters at all.

What tense is menulis here? Does it mean wrote, is writing, or writes?

Indonesian verbs like menulis do not change form for tense. Menulis simply means to write / writing in a neutral way.

The actual time (past, present, future) is determined by context or by adding time words:

Past:
- Remaja itu tadi menulis puisi… = earlier, the teenager wrote a poem…
- Remaja itu kemarin menulis puisi… = yesterday, the teenager wrote a poem…
Present (ongoing):
- Remaja itu sedang menulis puisi… = the teenager is writing a poem…
Future:
- Remaja itu akan menulis puisi… = the teenager will write a poem…

Without extra markers, Remaja itu menulis puisi… can be translated as wrote, is writing, or writes depending on the story context.

What is the difference between menulis puisi, menulis sebuah puisi, and menulis puisi-puisi?

They differ in count and emphasis:

menulis puisi
- Literally: to write poetry / to write poems
- Can mean a poem or poems or poetry in general, depending on context. Indonesian often leaves number vague.
menulis sebuah puisi
- sebuah marks one specific piece.
- This clearly means to write a (single) poem.
menulis puisi-puisi
- Reduplication usually indicates plural.
- puisi-puisi = poems (more than one).
- So menulis puisi-puisi = to write poems (several).

In your sentence, menulis puisi is fine and natural; you don’t have to mark singular or plural unless it’s important.

What does tentang do here, and where should it go in the sentence?

Tentang means about / regarding / concerning.

Usage:

menulis puisi tentang kakek dan nenek
= to write a poem about (the) grandfather and grandmother

The usual pattern is:

[verb] + [object] + tentang + [topic]

So:

menulis puisi tentang cinta = write a poem about love
membaca buku tentang sejarah = read a book about history

Putting tentang somewhere else, like tentang menulis puisi kakek dan nenek, would change the meaning or sound unnatural. Keep tentang right before the thing that is the topic of the poem/book/talk.

Why is it just kakek dan nenek, without anything like his or her? How would I say about his grandparents?

Indonesian often omits possessives when the context makes ownership obvious. Kakek dan nenek can mean:

(the) grandfather and grandmother in general, or
his/her grandparents, if the context clearly refers to the teenager’s family.

To make “his/her grandparents” explicit, you add ‑nya:

tentang kakek dan neneknya
= about his/her grandfather and grandmother
= about his/her grandparents

So:

Remaja itu menulis puisi tentang kakek dan nenek di buku harian.
Could be general or context-dependent.
Remaja itu menulis puisi tentang kakek dan neneknya di buku harian.
Clearly: about his/her grandparents.

Is kakek dan nenek exactly the same as saying grandparents in English?

Almost, but not exactly the same in form.

kakek = grandfather
nenek = grandmother
kakek dan nenek = grandfather and grandmother (a pair of them)

There’s also a combined form:

kakek-nenek = grandparents (as a plural group)

So you could say:

menulis puisi tentang kakek dan neneknya
= wrote a poem about his/her grandfather and grandmother (as individuals)
menulis puisi tentang kakek-neneknya
= wrote a poem about his/her grandparents (more like the English collective)

What exactly does buku harian mean? Is harian just daily?

Literally:

buku = book
harian = daily / of the day

But together, buku harian is a fixed expression meaning diary / journal (a book where you write about your day).

So:

buku harian = diary
di buku harian = in (the) diary

Harian by itself can mean daily or show up in words like:

koran harian = daily newspaper
program harian = daily schedule

Here, though, buku harian should be understood as a single unit: diary.

Could I replace buku harian with diari or jurnal? Are they the same?

They’re similar but with slight differences in usage and style:

buku harian
- Very common, neutral Indonesian.
- Strong association with a personal diary (feelings, daily events).
diari
- Loanword (from English diary).
- Used; sounds a bit more modern/urban or slightly English-influenced.
- Often interchangeable with buku harian in casual contexts.
jurnal
- More like journal/log, can be:
  - academic journal (jurnal ilmiah)
  - research log
  - reflective journal
- Less likely for a typical teenager’s private diary, unless the context is more formal or academic.

So you can say:

Remaja itu menulis puisi di buku hariannya. (very natural)
Remaja itu menulis puisi di diarinya. (also understandable and used)

But buku harian is the safest neutral choice.

What does di mean here, and could I use dalam or pada instead?

Di is a basic preposition for location, usually in / at / on depending on the noun.

di buku harian = in the diary
(literally: at / in the diary)

Alternatives:

dalam buku harian
- Also “in the diary”
- dalam emphasizes inside, a bit more explicit but still natural.
pada buku harian
- Grammatically possible but sounds odd/unnatural in this context.
- pada is more common with abstract objects (e.g., pada kesempatan ini, pada hari Senin) or indirect objects.

For a physical location like this, di buku harian is the natural choice.

Can the position of di buku harian change? For example, is Remaja itu di buku harian menulis puisi… correct?

The most natural order is what you have:

Remaja itu menulis puisi tentang kakek dan nenek di buku harian.

Typical pattern: Subject – Verb – Object – (extra info like place/time).

Other positions are possible but feel marked or unnatural in normal speech:

Remaja itu di buku harian menulis puisi tentang kakek dan nenek.
- Grammatically understandable, but sounds awkward; it gives unusual emphasis on di buku harian.

If you really want to emphasize the location, you’d more likely say:

Di buku hariannya, remaja itu menulis puisi tentang kakek dan nenek.
= In his/her diary, the teenager wrote a poem about his/her grandparents.

So: keep di buku harian at the end for the neutral word order.

Can I drop itu and just say Remaja menulis puisi…? What changes?

Yes, you can. The nuance changes slightly:

Remaja itu menulis puisi…
- Refers to a specific teenager the listener already knows about.
- Roughly: the teenager / that teenager wrote a poem…
Remaja menulis puisi…
- More general, could mean teenagers (in general) write poems…
- Or it might sound like you’re introducing a teenager for the first time in a very generic way.

If you are talking about one known individual, remaja itu is more natural. If you mean the category “teenagers”, you’d usually make it plural: para remaja or remaja-remaja.

Could I replace remaja itu with dia? When should I use a noun vs dia?

Yes, if the person has already been mentioned, using dia is natural:

Remaja itu menulis puisi tentang kakek dan nenek di buku harian. Dia menulis setiap malam.
= That teenager wrote a poem… He/She writes every night.

Guideline:

Use the full noun (remaja itu) when:
- You introduce the person for the first time.
- You want to be explicit about who you’re talking about.
Use dia when:
- It’s already clear who the person is.
- You want to avoid repeating the noun.

So you usually start with remaja itu, then continue with dia in later sentences.