Tolong beri tahu saya kalau jadwal rapat berubah.

Tolong makes the sentence a polite request, similar to please in English.

So Tolong beri tahu saya ... means Please let me know ...

Without tolong, the sentence would sound more direct:

• Beri tahu saya kalau jadwal rapat berubah. = Let me know if the meeting schedule changes.

That is still possible, but tolong softens it.

Beri tahu is a very common Indonesian expression meaning to let someone know, to inform someone, or to tell someone.

Literally:

• beri = give
• tahu = know

But as a set expression, beri tahu means give information / let someone know.

So:

• beri tahu saya = let me know
• memberi tahu saya = to let me know / informing me

Because this sentence is a request/command.

In Indonesian, imperatives often use the base form rather than the meN- form:

• memberi tahu = to inform
• beri tahu! = inform! / let me know!

So:

• Tolong memberi tahu saya ... sounds less natural here
• Tolong beri tahu saya ... is the normal way to say it

In standard writing, it is usually written as two words: beri tahu.

The same applies to:

• memberi tahu
• kasih tahu

You may sometimes see beritahu in informal writing, but for learners, beri tahu is the safest standard form here.

Here kalau means if.

So:

• kalau jadwal rapat berubah = if the meeting schedule changes

In other contexts, kalau can sometimes feel like when or whenever, depending on the situation, but in this sentence the natural English meaning is clearly if.

A more formal alternative is jika:

• Tolong beri tahu saya jika jadwal rapat berubah.

Both are correct, but jika sounds more formal and written.

Because Indonesian noun phrases usually put the main noun first and the modifier after it.

So:

• jadwal = schedule
• rapat = meeting
• jadwal rapat = meeting schedule / schedule of the meeting

This is the normal Indonesian pattern:

• buku pelajaran = textbook
• kantor pos = post office
• jadwal rapat = meeting schedule

English often does the opposite by putting the modifier first.

Berubah means to change or to become different.

It is intransitive, so it describes something that changes by itself:

• Jadwal rapat berubah. = The meeting schedule changes / has changed.

Compare:

• berubah = change, become different
• mengubah = change something, alter something

So:

• Jadwal rapat berubah. = The schedule changes.
• Mereka mengubah jadwal rapat. = They changed the meeting schedule.

That distinction is very important in Indonesian.

Indonesian verbs do not usually show tense the way English verbs do. The form berubah itself does not tell you whether it is present, future, or past.

The time is understood from context.

So this sentence could mean:

• Please let me know if the meeting schedule changes
• Please let me know if the meeting schedule has changed
• Please let me know if the meeting schedule is changing

In most situations, English speakers would naturally translate it as Please let me know if the meeting schedule changes or ... if the meeting schedule changes/has changed, depending on context.

If Indonesian needs to be more specific, it can add time words:

• sudah berubah = has already changed
• akan berubah = will change

Yes, you could use aku, but saya is more neutral and polite.

• saya = polite/neutral I / me
• aku = more casual and personal

So:

• Tolong beri tahu saya ... sounds appropriate in many normal situations
• Tolong beri tahu aku ... sounds more casual and familiar

If you are talking to coworkers, a teacher, or someone you do not know very well, saya is usually the safer choice.

It is best described as neutral polite.

• tolong makes it polite
• saya makes it fairly neutral and appropriate
• kalau is a little more conversational than jika

So the sentence works well in everyday spoken and written Indonesian.

If you want a slightly more formal version, you could say:

• Mohon beri tahu saya jika jadwal rapat berubah.

That sounds more formal and professional.

Yes. Kasih tahu is very common in everyday Indonesian.

So:

• Tolong kasih tahu saya kalau jadwal rapat berubah.

This means the same thing, but it sounds a bit more informal and conversational.

A rough comparison:

• beri tahu = neutral
• kasih tahu = more casual
• informasikan = more formal

All three can fit the general meaning let me know, but they differ in register.