Learn Hardcore Indonesian: Keluarga kami berlibur di akhir tahun. - Our family goes on vacation at the end of the year.

So keluarga kami is the natural way to say our family.
Kami keluarga on its own is not how you say “our family”; it would sound more like “we (are) a family,” and even then you’d usually add something more (e.g. Kami keluarga yang sederhana – “We are a simple family”).

What’s the difference between kami and kita here? Could I say keluarga kita?

Both kami and kita mean “we / us”, but:

kami = we (excluding the listener)
kita = we (including the listener)

So:

keluarga kami = our family (not including you)
keluarga kita = our family (including you as part of this family)

Which one is correct depends on who is speaking and who is being spoken to:

If I’m talking to a friend about my family:
- Keluarga kami berlibur di akhir tahun.
  = My/our family (me, my spouse, kids, etc., but not you) go on vacation at the end of the year.
If I’m talking to my sibling about our shared family (parents, siblings, etc.):
- Keluarga kita berlibur di akhir tahun.
  = Our family (including you) go on vacation at the end of the year.

So keluarga kami in the sentence suggests the listener is not part of that family.

What is the role of ber- in berlibur? Why not just libur?

libur by itself is usually a noun or adjective:
- libur = holiday, break, off (as in not working / no school)
- Hari ini libur. = Today is a holiday / We’re off today.
berlibur is ber- + libur, forming an intransitive verb meaning “to go on vacation / to take a holiday”:
- Kami berlibur di Bali. = We go on vacation in Bali.

So in the sentence:

Keluarga kami berlibur di akhir tahun.
→ berlibur is the main verb: Our family goes on vacation / takes a holiday at the end of the year.

Using only libur as a verb here would be ungrammatical; you need berlibur for the action “to vacation.”

Is berlibur like the English present tense, past tense, or future tense? How do I know the time?

Indonesian verbs don’t change form for tense. Berlbur always stays berlibur.
Time is shown by context or time expressions, such as:

kemarin (yesterday)
tadi (earlier)
sekarang (now)
nanti (later)
akan (will)
setiap (every)

Your sentence:

Keluarga kami berlibur di akhir tahun.

By itself, this most naturally means a general or habitual action:

Our family (usually / generally / every year) goes on vacation at the end of the year.

If you want to emphasize specific time, you add adverbs:

Keluarga kami akan berlibur di akhir tahun.
= Our family will go on vacation at the end of the year.
Tahun lalu, keluarga kami berlibur di akhir tahun.
= Last year, our family went on vacation at the end of the year.

The verb form does not change; only the time words change.

Why do we use di in di akhir tahun? Is it like “in”, “on”, or “at”?

In time expressions, di is usually translated as “at”:

di pagi hari = in the morning
di malam hari = at night
di akhir tahun = at the end of the year

In di akhir tahun, di marks a point in time:

di (at) + akhir (end) + tahun (year)
→ at the end of the year

So here di corresponds most closely to English “at”, but depending on the phrase and translation, it can also be rendered as “in” or “on.”

Could we say pada akhir tahun instead of di akhir tahun? Is there any difference?

Yes, you can say:

Keluarga kami berlibur pada akhir tahun.

In time expressions, di and pada often overlap:

di akhir tahun
pada akhir tahun

Both mean “at the end of the year”.
Subtle differences:

pada is a bit more formal / bookish, common in writing, speeches, news, etc.
di is very common in everyday spoken Indonesian and is perfectly correct.

So in normal conversation, di akhir tahun is completely natural.

Why is it akhir tahun and not akhir dari tahun for “the end of the year”?

In Indonesian, noun + noun is usually made just by placing them side by side, without a word like “of”:

akhir tahun = end of (the) year
ujung minggu = end of the week (weekend)
pintu rumah = door of the house

So:

akhir (end) + tahun (year)
→ akhir tahun = the end of the year

You can say akhir dari tahun, but it sounds less natural or more “translated” from English. The normal phrase is simply akhir tahun.

Can we drop keluarga and just say Kami berlibur di akhir tahun?

Yes, Kami berlibur di akhir tahun is completely correct and very natural.

The difference is:

Keluarga kami berlibur di akhir tahun.
Emphasizes the family as a unit going on vacation.
Kami berlibur di akhir tahun.
Just “We go on vacation at the end of the year” (it happens to be the family, but that’s only clear from context).

So including keluarga makes it explicit that it is the family that goes on vacation.

Is keluarga grammatically singular or plural? Why doesn’t the verb change?

Keluarga is grammatically treated as a singular noun meaning “family” (a group):

Keluarga kami besar. = Our family is big.

Indonesian verbs don’t change for number (singular/plural), so:

Keluarga kami berlibur di akhir tahun.
Mereka berlibur di akhir tahun.

In both cases, the verb stays berlibur. There is:

no -s like English “goes”
no special plural verb form

Number (singular vs plural) is understood from nouns and pronouns, not from verb endings.

Can I say Keluarga kami pergi berlibur di akhir tahun? What’s the difference if I add pergi?

Yes, that sentence is also correct:

Keluarga kami pergi berlibur di akhir tahun.
= Our family goes (away) to have a vacation at the end of the year.

Differences in nuance:

berlibur alone already means “to go on vacation / to take a holiday”.
Adding pergi (to go) emphasizes the movement or going away aspect:
- Keluarga kami berlibur di akhir tahun.
  Neutral: Our family vacations at the end of the year.
- Keluarga kami pergi berlibur di akhir tahun.
  Slightly more like: Our family goes away on vacation at the end of the year.

In many contexts you can safely omit pergi, and berlibur is enough.

Could I say Keluarga kami libur di akhir tahun instead of berlibur?

Normally, no. Libur in that kind of sentence sounds wrong. Explanation:

libur is more like a state: to be off / to be on holiday (no work, no school)
- Besok kita libur. = Tomorrow we’re off / have a day off.
berlibur is clearly an activity: to go on vacation / take a holiday
- Kami berlibur di Bali. = We go on vacation in Bali.

In Keluarga kami berlibur di akhir tahun, the idea is an active vacation rather than just “we happen not to work then.”
So you should keep berlibur here.

Can I drop di and say Keluarga kami berlibur akhir tahun?

In informal spoken Indonesian, people often drop di in some time expressions, so you may hear:

Keluarga kami berlibur akhir tahun.

This is commonly understood in casual conversation and sounds natural in many regions.

However, for:

clear, standard, and especially written Indonesian,
di akhir tahun is preferable and more correct:
Keluarga kami berlibur di akhir tahun.

So:

Informal speech: OK to omit di in many cases.
Formal / careful Indonesian: better to include di.

If I want to say “every year” instead of just “at the end of the year,” how would I change the sentence?

To show repetition / every year, add setiap tahun or setiap akhir tahun:

Keluarga kami berlibur setiap tahun.
= Our family goes on vacation every year.
Keluarga kami berlibur setiap akhir tahun.
= Our family goes on vacation at the end of every year.

You can also combine with “this year / last year / next year”:

Tahun ini, keluarga kami berlibur di akhir tahun.
= This year, our family will go on vacation at the end of the year.

Here again, the verb berlibur doesn’t change; only the time expressions change.