Learn Hardcore Indonesian: Kami makan malam di restoran Jepang kecil, dan pelayan di sana sangat ramah. - We had dinner at a small Japanese restaurant, and the waiter/waitress there was very friendly.

As a verb phrase: makan malam = to have dinner
- Kami makan malam di rumah. = We have dinner at home.
As a noun: makan malam = dinner (the event/meal)
- Makan malam sudah siap. = Dinner is ready.

In your sentence, kami makan malam is best understood as we had dinner (verb phrase).

How do we know this sentence is in the past? There’s no past tense word.

Indonesian usually does not change the verb form for tense. Time is understood from:

Context (a story already understood as past)
Time words:
- tadi malam = last night
- kemarin = yesterday

If you want to make it clearly past, you can add a time word:

Kami tadi malam makan malam di restoran Jepang kecil...
Kemarin kami makan malam di restoran Jepang kecil...

But grammatically, kami makan malam by itself can be past, present, or future; context decides.

Why is the word order restoran Jepang kecil, not kecil restoran Jepang?

In Indonesian, the basic pattern is:

Noun + (describing word(s))

Here:

restoran = restaurant (noun)
Jepang = Japanese (type / style)
kecil = small (size)

So restoran Jepang kecil literally feels like restaurant (that is) Japanese (and) small.

You can think of it as:

restoran Jepang = Japanese restaurant
restoran Jepang kecil = small Japanese restaurant

Putting kecil before restoran (kecil restoran Jepang) is not natural in Indonesian.

Could we say restoran kecil Jepang instead of restoran Jepang kecil?

No, restoran kecil Jepang sounds odd or confusing.

The neutral and natural order is:

restoran Jepang kecil = a small Japanese restaurant

If you really want to emphasize small, you could also say:

restoran Jepang yang kecil
(literally: the Japanese restaurant that is small)

But everyday speech will just use restoran Jepang kecil.

What exactly does Jepang mean here? Country name or adjective Japanese?

Jepang is the country name (Japan), but Indonesian commonly uses country names as adjectives:

restoran Jepang = Japanese restaurant
makanan Indonesia = Indonesian food
film Amerika = American movie

So Jepang here works like an adjective meaning Japanese-style / from Japan.

Why is it di restoran and not ke restoran?

di = at / in (location)
ke = to (movement towards)

In this sentence, the focus is on the place where the action happens:

Kami makan malam di restoran Jepang kecil
= We had dinner at a small Japanese restaurant.

If you want to talk about going there, you use ke:

Kami pergi ke restoran Jepang kecil untuk makan malam.
= We went to a small Japanese restaurant to have dinner.

So: di = where something happens; ke = where you go.

What does pelayan mean exactly? Is it just waiter?

Pelayan literally means someone who serves. In practice:

In a restaurant context, pelayan = waiter / waitress / server (gender-neutral).
In other contexts, pelayan can mean servant or attendant, depending on context and tone.

More formal or specifically restaurant terms include:

pramusaji = food server / waiter (quite formal; less used in casual speech)

In everyday casual speech for a restaurant, pelayan is normal and natural.

Why is it pelayan di sana and not just pelayan or pelayan itu?

Each choice has a slightly different nuance:

pelayan = the waiter (understood from context, but not specified which one)
pelayan itu = that waiter / the waiter (more specific, often already known in the conversation or being pointed at)
pelayan di sana = the waiter there (at that place), linking the waiter clearly to that restaurant/location.

Here, di sana reminds you:

It’s the waiter at that restaurant (the one we just mentioned), not some random waiter elsewhere.

What is the function of di sana in this sentence?

Di sana = there / at that place.

In the sentence:

...dan pelayan di sana sangat ramah.
= ...and the waiter there was very friendly.

It refers back to restoran Jepang kecil:

di sana = at that small Japanese restaurant.

Why is there no yang before sangat ramah? Could we say pelayan yang sangat ramah?

Both are possible, but slightly different:

pelayan sangat ramah
= the waiter is/was very friendly (simple description).
pelayan yang sangat ramah
= the waiter who is very friendly (like a relative clause; often contrasts with others or emphasizes that specific quality).

In your sentence:

pelayan di sana sangat ramah is the simplest, most natural way.
pelayan di sana yang sangat ramah would strongly emphasize the friendliness, as if selecting that waiter out of a group for that trait.

What does sangat ramah mean, and are there other ways to say very friendly?

ramah = friendly, warm, pleasant (about people)
sangat = very (formal/neutral)

So sangat ramah = very friendly.

Other common options:

ramah sekali = very friendly
ramah banget = very friendly (informal / colloquial)

All mean very friendly; sangat and sekali are more neutral, banget is casual.

How do we know if pelayan is singular (one waiter) or plural (several waiters)?

Indonesian does not usually mark plural on nouns. Pelayan can mean:

waiter / the waiter
waiters / the waiters

Context decides. If you clearly want to say several waiters, you can use:

para pelayan = the (group of) waiters
banyak pelayan = many waiters
beberapa pelayan = several waiters

In your sentence, the natural English translation is the waiter there, but in Indonesian pelayan di sana could be understood as one or more, depending on context.

Could we drop kami and just say Makan malam di restoran Jepang kecil...?

Yes, Indonesian often drops the subject when it is clear from context.

Makan malam di restoran Jepang kecil, dan pelayan di sana sangat ramah.
Could be understood as: (We) had dinner at a small Japanese restaurant, and the waiter there was very friendly.

However:

Including kami makes it clear it is we,
Without context, the subject could be I, we, they, etc.

In teaching materials and clear writing, kami is kept to avoid ambiguity.