Learn Hardcore Malay: Kawan saya merancang satu kejutan kecil untuk hari lahir gurunya. - My friend is planning a small surprise for her/his teacher’s birthday.

So kawan (friend) comes first, and saya (I/my) comes after it to show possession.
Saya kawan would mean something like I (am a) friend, not my friend.

Does kawan saya mean my friend or my friends?

It can mean either, depending on context.

Malay usually doesn’t mark plural with an ending like English -s.

kawan saya can be my friend (one person)
kawan-kawan saya clearly means my friends (more than one)
In casual speech, people sometimes just say kawan saya even when they mean more than one; the listener understands from context.

In your sentence, we usually imagine one friend, but it could be plural if the wider context mentions a group.

What is the difference between merancang and rancang?

Rancang is the root verb (to plan), and merancang is the active verb form made with the prefix meN-.

rancang – base form (you might see this in dictionaries, headlines, or after certain particles like nak, sudah, akan)
merancang – normal, fully inflected verb used in sentences:
- Dia merancang sesuatu. – He/She is planning something.

In a full sentence like yours, merancang is the natural choice:
Kawan saya merancang… = My friend is/was planning…

Why is there no separate word for “is/was” in Kawan saya merancang…?

Malay typically doesn’t use a separate verb “to be” (like is, am, are) before verbs.

English: My friend *is planning…*
Malay: Kawan saya merancang…

The tense (present, past, future) is worked out from context or from time words:

tadi – earlier, just now
semalam – last night
esok – tomorrow
akan – will (future marker)

So you could say:

Kawan saya merancang… – My friend is/was planning… (context decides)
Kawan saya akan merancang… – My friend will plan…

Why do we use satu here? Is it like “a” or “one” in English?

Satu literally means “one”, but in many sentences it functions like the English “a/an”.

satu kejutan kecil = one small surprise or a small surprise

Often, Malay can omit this:

Kawan saya merancang kejutan kecil… – My friend planned a small surprise… (still natural)

Adding satu can make it feel a bit more specific/emphatic (one particular surprise), but it isn’t always necessary.

Would sebuah kejutan kecil be better than satu kejutan kecil?

Both are possible:

satu kejutan kecil – literally one small surprise
sebuah kejutan kecil – uses the classifier buah, which often goes with general/countable things

In practice:

sebuah kejutan kecil often sounds a bit more polished/natural in careful writing or speech.
satu kejutan kecil is also acceptable and understandable, especially in everyday conversation.

So you could say either:

Kawan saya merancang satu kejutan kecil…
Kawan saya merancang sebuah kejutan kecil…

Why is the adjective after the noun in kejutan kecil, not kecil kejutan?

Malay usually puts adjectives after the noun they describe.

kejutan kecil – small surprise (literally surprise small)
buku baru – new book
rumah besar – big house

So the normal order is:

noun + adjective

Putting kecil first (e.g. kecil kejutan) would be wrong in standard Malay.

What does untuk do in this sentence? Can I use other words instead?

Untuk means “for” (indicating purpose or benefit).

…kejutan kecil untuk hari lahir gurunya.
– …a small surprise for his/her teacher’s birthday.

Other possibilities:

bagi – also “for”, slightly more formal or written
kepada – usually “to”, often for giving something to someone

In this sentence:

untuk hari lahir gurunya is the most natural way to say for his/her teacher’s birthday.
bagi hari lahir gurunya is possible but less common in everyday speech.

What does hari lahir mean, and how is it different from hari jadi or ulang tahun?

All are related to “birthday”:

hari lahir – literally day of birth, common and neutral
hari jadi – also widely used, especially in Malaysia, more colloquial
ulang tahun – literally anniversary (used for birthdays and other anniversaries), feels a bit more formal

Examples:

hari lahir gurunya – his/her teacher’s birthday
hari jadi saya – my birthday
ulang tahun perkahwinan – wedding anniversary

In your sentence, hari lahir gurunya = his/her teacher’s birthday.

What exactly does gurunya mean? Whose teacher is it?

Gurunya is made of:

guru – teacher
-nya – a suffix often meaning “his/her/its” or “the” (definiteness)

So gurunya usually means:

his/her teacher
- Here, it most naturally refers to the friend’s teacher (the teacher of my friend).

However, -nya can sometimes just make a noun definite, like the teacher (when the owner is already known from context). Without more context, English speakers usually translate it as:

for his/her teacher’s birthday

Could we say hari lahirnya instead of hari lahir gurunya?

Yes, but the meaning shifts slightly.

hari lahir gurunya – literally the birthday of his/her teacher
hari lahirnya – his/her birthday (the -nya refers to the most relevant person in context)

So:

If the focus is clearly on the teacher, hari lahir gurunya is clearer.
hari lahirnya could refer to my friend’s birthday or the teacher’s birthday, depending on context.

Is kawan the only word for “friend”? What about rakan or sahabat?

There are several words:

kawan – friend; very common, neutral, everyday
rakan – friend/colleague/associate; sounds more formal (used in official writing, workplaces)
sahabat – close friend; suggests a deeper, more intimate friendship

Your sentence:

Kawan saya merancang… – My friend planned… (normal, everyday tone)

You could say Sahabat saya merancang… if you want to emphasise a close friendship.

Can I use aku instead of saya in this sentence?

Grammatically, yes, but the level of formality changes.

saya – polite, neutral; used with strangers, teachers, at work, in writing
aku – informal, used with close friends/family, or in casual contexts

So:

Kawan saya merancang… – neutral/polite
Kawan aku merancang… – more casual and intimate

Choose based on who you’re talking to and the situation.