Ulang tahun kakak perempuan saya jatuh pada Januari, jadi keluarga kami berkumpul di rumah nenek.

Literally, ulang means repeat and tahun means year, so ulang tahun is like the repeating of a year. In natural Indonesian, it means birthday or sometimes anniversary, depending on context.

In this sentence, ulang tahun kakak perempuan saya means my older sister’s birthday.

In Indonesian, kakak means older sibling. If you want to specify gender, you add:

• kakak perempuan = older sister
• kakak laki-laki = older brother

So kakak perempuan saya is specifically my older sister.

If you just say saudara perempuan, that means female sibling/sister, but it sounds more formal and does not tell you whether she is older or younger.

Indonesian often puts the main noun first, followed by words that describe or specify it.

So:

• ulang tahun = birthday
• kakak perempuan saya = my older sister

Together:

• ulang tahun kakak perempuan saya = my older sister’s birthday

This is a very common Indonesian pattern: thing + owner.

For example:

• rumah saya = my house
• nama teman itu = that friend’s name
• ulang tahun kakak perempuan saya = my older sister’s birthday

Because Indonesian usually does possession without a separate word like English ’s.

English:

• my sister’s birthday

Indonesian:

• ulang tahun kakak perempuan saya

The order itself shows the relationship:

• birthday + my older sister

So Indonesian often expresses possession just by putting the possessed thing first and the owner after it.

Yes, jatuh often means to fall, but in date expressions it can mean to fall on / to occur in.

So:

• Ulang tahun kakak perempuan saya jatuh pada Januari
  = My older sister’s birthday falls in January

This is an idiomatic and common way to talk about dates, schedules, and calendar timing.

You can also see similar usage in sentences like:

• Lebaran jatuh pada bulan April tahun ini.
  = Eid falls in April this year.

Pada is often used with points in time, especially in somewhat careful or formal Indonesian.

So:

• jatuh pada Januari = falls in January

That said, in everyday speech, Indonesians may also say:

• jatuh di bulan Januari
• or even just jatuh Januari, depending on style and context

In this sentence, pada Januari sounds natural and correct.

Sometimes yes, especially in casual speech, but pada Januari is usually safer and more standard in this kind of sentence.

A rough guide:

• pada Januari = standard/formal-ish, often used with dates and time references
• di Januari = heard in speech, but less preferred by some speakers in careful writing
• pada bulan Januari = also correct, a bit fuller
• di bulan Januari = very common in conversation

So for learners, jatuh pada Januari is a very good model to follow.

Here, jadi means so, therefore, or as a result.

It connects the two ideas:

• My older sister’s birthday falls in January
• so our family gathers at grandmother’s house

So jadi shows a result or consequence.

Be careful: jadi can also mean become, depending on context. But in this sentence, it clearly means so.

This is a very important Indonesian distinction.

• kami = we/us, excluding the person being spoken to
• kita = we/us, including the person being spoken to

So keluarga kami means our family, but it does not include the listener.

That makes sense here, because the speaker is talking about their family gathering, not necessarily the listener’s family too.

Because keluarga kami means our family, where:

• keluarga = family
• kami = our/us

Again, Indonesian often puts the noun first and the possessor after it:

• rumah kami = our house
• ibu saya = my mother
• keluarga kami = our family

Kami keluarga would mean something more like we are family or we, the family, depending on context, so it is not the same structure.

Berkumpul means to gather, to get together, or to assemble.

The root is kumpul, which is related to gathering or collecting. The prefix ber- often makes an intransitive verb, often meaning something like to do or to be engaged in that action.

So:

• kumpul = gather / hang out together in casual use
• berkumpul = to gather, to assemble

In this sentence, keluarga kami berkumpul means our family gathers.

In casual conversation, people often also say just kumpul:

• Kami kumpul di rumah nenek.

But berkumpul is a bit more standard.

Because di means at/in, while ke means to.

So:

• berkumpul di rumah nenek = gather at grandma’s house
• pergi ke rumah nenek = go to grandma’s house

In this sentence, the focus is on where the family gathers, not on the movement toward that place. So di rumah nenek is the correct choice.

Yes. Just like earlier in the sentence, Indonesian often shows possession by word order.

• rumah nenek = grandmother’s house
• literally: house grandmother

This is a normal and very common structure.

If the context is already clear, Indonesian often leaves out extra words like my. So di rumah nenek will often naturally be understood as at grandma’s house or at my grandmother’s house, depending on the situation.

Because Indonesian often omits information that is already obvious from context.

The sentence already has:

• kakak perempuan saya = my older sister
• keluarga kami = our family

So when it says di rumah nenek, listeners will usually understand that this is the grandmother connected to that family. Saying di rumah nenek saya is also possible, but it is not always necessary.

Both can be correct:

• di rumah nenek = at grandma’s house
• di rumah nenek saya = at my grandmother’s house

The shorter version sounds natural when the relationship is clear.

Indonesian verbs do not change the way English verbs do for past, present, or future.

So berkumpul can mean:

• gather
• are gathering
• gathered
• will gather

The exact time usually comes from context, time words, or the larger situation.

In this sentence, because jatuh pada Januari sounds like a general fact and the second clause follows from it, the sentence naturally reads as a habitual or general present:

• My older sister’s birthday falls in January, so our family gathers at grandmother’s house.

If you wanted to make it clearly past, you could add something like:

• tahun lalu = last year
• kemarin = yesterday

Yes, it is natural and correct.

It has a slightly careful, standard feel because of words like:

• jatuh pada
• berkumpul

A more casual version might be:

• Ulang tahun kakak perempuan saya ada di bulan Januari, jadi keluarga kami kumpul di rumah nenek.

But the original sentence is perfectly good Indonesian and is a nice model for learners.