Diskon berlaku mulai pagi ini.

In this sentence, berlaku means to be valid, to apply, or to be in effect.

So Diskon berlaku mulai pagi ini means the discount is now officially active starting this morning.

Berlaku is often used for things like:

• discounts
• rules
• laws
• tickets
• promotions
• documents

Examples:

• Tiket ini berlaku sampai besok. = This ticket is valid until tomorrow.
• Aturan baru berlaku hari ini. = The new rule takes effect today.

Indonesian does not normally use articles like the or a/an the way English does.

So diskon can mean:

• a discount
• the discount
• discounts

The exact meaning depends on context.

In this sentence, English would usually say The discount or Discounts, but Indonesian just says diskon.

Yes. In this sentence, diskon is the subject, and berlaku is the predicate.

A simple breakdown is:

• Diskon = discount
• berlaku = is valid / applies
• mulai pagi ini = starting this morning

So the structure is basically:

Subject + predicate + time expression

Here, mulai means starting or beginning from.

So:

• mulai pagi ini = starting this morning

In other contexts, mulai can also work as a main verb meaning to begin or to start.

Examples:

• Saya mulai belajar. = I started studying.
• Promo berlaku mulai besok. = The promotion is valid starting tomorrow.

In your sentence, it introduces the starting time of the discount’s validity.

Pagi ini is the normal way to say this morning.

It is made up of:

• pagi = morning
• ini = this

So literally it is morning this, but that is just normal Indonesian word order.

This same pattern appears in:

• hari ini = today
• malam ini = tonight
• minggu ini = this week
• bulan ini = this month

Yes, but the nuance is a little different.

• Diskon berlaku mulai pagi ini = very natural; starting this morning
• Diskon berlaku dari pagi ini = from this morning
• Diskon berlaku mulai dari pagi ini = starting from this morning

All are understandable, but mulai pagi ini is concise and very common.

Mulai dari can sound a bit more explicit or slightly heavier stylistically. In many everyday situations, mulai pagi ini is the smoothest choice.

This is a very useful distinction.

• berlaku focuses on something being valid / taking effect
• dimulai focuses on something being started / beginning

So:

• Diskon berlaku mulai pagi ini = The discount is valid starting this morning.
• Diskon dimulai pagi ini = The discount started this morning.

These are close in meaning, but not identical.

Berlaku is especially common when talking about official validity, applicability, or effective dates.

Yes, it is a complete sentence.

Indonesian often does not use a separate word for is/am/are the way English does. In this sentence, berlaku already acts as the predicate, so nothing else is needed.

Compare:

• Diskon berlaku mulai pagi ini. = The discount is valid starting this morning.
• Aturan itu berlaku sekarang. = That rule is in effect now.

So even without an Indonesian equivalent of is, the sentence is fully natural and complete.

By itself, diskon does not clearly show singular or plural. Indonesian nouns usually do not change form for number.

So diskon could mean:

• one discount
• discounts in general

Context tells you which meaning is intended.

If someone really wants to make it clearly plural, they might say:

• diskon-diskon

But in real life, that is often unnecessary.

It is fairly neutral and very natural. It would work well in:

• advertisements
• store signs
• announcements
• business messages

It sounds clear and standard.

If you wanted a slightly more promotional style, you might see:

• Diskon mulai berlaku pagi ini.
• Promo berlaku mulai pagi ini.

These are also natural. The original sentence is perfectly good standard Indonesian.

Yes. Berlaku is a very common word for something that applies, is valid, or takes effect.

Examples:

• Peraturan ini berlaku untuk semua orang. = This rule applies to everyone.
• Paspor saya masih berlaku. = My passport is still valid.
• Harga promo berlaku sampai akhir bulan. = The promotional price is valid until the end of the month.
• Undang-undang baru berlaku tahun depan. = The new law takes effect next year.

So learning berlaku is very useful beyond this one sentence.