Learn Hardcore Indonesian: Saya kadang melihat iklan buku baru dan menyimpan rekomendasi itu di ponsel. - Sometimes I see ads for new books and save those recommendations on my phone.

saya = neutral / polite, safe in almost all situations (talking to strangers, at work, in writing, etc.).
aku = informal, used with close friends, family, or people of the same age in casual situations.

So in this sentence, saya gives a neutral or slightly formal tone. You could say:

Aku kadang melihat iklan buku baru dan menyimpan rekomendasi itu di ponsel.

That would sound more casual and personal, for example in a chat with friends.

What is the difference between kadang and kadang-kadang? Can I use both here?

Both kadang and kadang-kadang mean “sometimes”.

kadang-kadang is the full, slightly more explicit form.
kadang is a shortened, very common spoken form; it sounds natural and a bit more casual.

You can use either here without changing the meaning much:

Saya kadang melihat…
Saya kadang-kadang melihat…

Both are correct. In careful writing, you might see kadang-kadang more often, but kadang is extremely common in everyday speech.

Where can kadang go in the sentence? Is Saya kadang melihat… the only option?

The most natural positions are:

Saya kadang melihat iklan buku baru…
Kadang saya melihat iklan buku baru…

Both are fine. The second one slightly emphasizes “sometimes”.

These, however, are not natural:

✗ Saya melihat kadang iklan buku baru…
✗ Saya melihat iklan buku baru kadang… (sounds awkward)

So put kadang either right after the subject (Saya) or at the very beginning of the sentence.

Why is it iklan buku baru and not iklan baru buku?

Indonesian usually puts describing words after the noun.

In iklan buku baru:

iklan = advertisement
buku = book
baru = new

The structure is:
iklan (advertisement) + buku baru (new book)
→ “advertisements of new books.”

If you said iklan baru buku, it would be confusing / incorrect, because:

iklan baru = new advertisement
buku is then left hanging at the end.

So the natural phrase for “ads for new books” is iklan buku baru.

Can iklan buku baru mean one ad or many ads? There’s no plural ending.

Indonesian usually does not mark plural with an ending like -s.

iklan buku baru can mean:

“a new book ad”
“new book ads”

The context decides whether it’s singular or plural. If you really want to emphasize plural, you could say:

banyak iklan buku baru = many new book ads
beberapa iklan buku baru = several new book ads

But the basic form iklan buku baru is flexible.

Why is it melihat here? Could I use menonton instead?

Both verbs are related to “seeing / watching,” but they’re used differently:

melihat = to see, to look at (general, not necessarily long)
menonton = to watch (usually something longer, like a movie, TV show, performance)

For ads, especially short ones you come across while scrolling or glancing at things, melihat iklan is more natural.

You can say menonton iklan, but that suggests you deliberately sit and watch ads as a “show”, which sounds unusual unless you’re, for example, analyzing commercials.

Why does the second verb phrase start with dan menyimpan, not dan saya menyimpan? Is it okay to drop the subject?

Yes, it’s very normal in Indonesian to omit the repeated subject when it’s the same as in the previous clause.

Saya kadang melihat iklan buku baru dan (saya) menyimpan rekomendasi itu di ponsel.

The subject saya is understood for both verbs:

saya melihat … dan (saya) menyimpan …

Adding saya again is not wrong, but it’s unnecessary and sounds a bit heavier:

Saya kadang melihat iklan buku baru dan saya menyimpan rekomendasi itu di ponsel. (correct but more emphatic or formal)

What exactly does rekomendasi itu mean? Why is itu there?

rekomendasi = recommendation
itu literally = that

In Indonesian, itu is used like:

A demonstrative (“that recommendation”)
A kind of definite marker, similar to “the” in English (“the recommendation”)

In this sentence, rekomendasi itu refers to:

the specific recommendation shown in the ad you just saw.

So itu points back to something already known in the context (the recommendation from the ad).

Could I say rekomendasi tersebut instead of rekomendasi itu?

Yes, but the tone changes:

rekomendasi itu = that recommendation (neutral, everyday speech)
rekomendasi tersebut = that recommendation (more formal, often written language, reports, articles)

Both refer to something already mentioned, but tersebut sounds more formal / written, while itu sounds neutral / conversational.

In normal spoken Indonesian, rekomendasi itu is more natural.

Why is it di ponsel? In English we say “on my phone”; shouldn’t it be something like “on” instead of di?

Indonesian uses di for many locations:

physical places: di rumah (at home), di kantor (at the office)
surfaces: di meja (on the table)
devices: di ponsel, di laptop, di komputer

So:

di ponsel literally is “at/on the phone,” and that covers English “on my phone.”

If you want to add “my”:

di ponsel saya = on my phone

Is ponsel the usual word? I often see HP or handphone.

All of these are common:

ponsel = short for “telepon seluler”; slightly more formal/standard
HP (pronounced “ha-pe”) = very common informal spoken word
handphone = widely used, especially in older or informal speech

So you might also hear:

… menyimpan rekomendasi itu di HP saya.

In neutral written language (like this example sentence), ponsel is a good choice.

What does menyimpan cover? Does it only mean “to save (digitally)”, or also “to keep / store” in general?

menyimpan is broader; it means to keep / store / save something so you can use it later. It can be:

physical:
- menyimpan uang di dompet = keep money in a wallet
- menyimpan buku di rak = store a book on a shelf
digital:
- menyimpan file di komputer = save a file on a computer
- menyimpan nomor telepon di ponsel = save a phone number on your phone

So in the sentence, menyimpan rekomendasi itu di ponsel very naturally means “saving that recommendation on the phone” (e.g., in notes, bookmarks, screenshots, etc.).

How do we know the sentence means a habit (“I sometimes do this”), and not something in the past or future?

Indonesian usually does not mark tense with verb endings. Instead, the meaning comes from:

context
time words like kadang (sometimes), sudah (already), akan (will), etc.

Here:

kadang signals a repeated / habitual action.
No word like sudah (already) or akan (will) is present.

So we naturally interpret it as habitual present:
“I sometimes see ads for new books and save the recommendations on my phone.”

Could I drop saya and just say Kadang melihat iklan buku baru…?

Native speakers do sometimes drop the subject in casual speech or writing if it’s very clear from context:

Kadang melihat iklan buku baru dan menyimpan rekomendasi itu di ponsel.

This could work in an informal setting (like texting), where it’s obvious you’re talking about yourself.

However, for clear, learner-friendly, and neutral sentences, it’s better to keep the subject:

Saya kadang melihat iklan buku baru…

So the example sentence is using the clearer, more standard form.