Saya baru makan siang.

Here, baru means just or recently.

So Saya baru makan siang means I just had lunch / I’ve just eaten lunch.

This is different from baru meaning new, as in baju baru = new clothes. Indonesian words often have more than one use, and the meaning depends on position and context.

Indonesian does not mark tense the way English does. There is no verb change like eat / ate / eaten.

Instead, Indonesian usually shows time through:

• context
• time words
• aspect words such as baru, sudah, sedang, belum

In Saya baru makan siang, the word baru tells you the action happened very recently, so the sentence is understood as I just ate lunch or I’ve just had lunch.

Literally, yes:

• makan = eat
• siang = daytime / noon

But together, makan siang is a normal fixed expression meaning to have lunch or lunch.

It works much like:

• sarapan = have breakfast / breakfast
• makan malam = have dinner / dinner

So you should learn makan siang as a common expression, not translate it word by word every time.

Because baru is modifying the action makan siang.

A common Indonesian pattern is:

Subject + adverb + verb

So:

• Saya baru makan siang = I just had lunch

If you move baru to the end, such as Saya makan siang baru, it sounds unnatural or changes the structure entirely.

Normally, no.

Saya baru makan siang means the lunch happened a short time ago, not that it is happening right now.

If you want to say I am eating lunch, Indonesian usually uses sedang:

• Saya sedang makan siang = I am having lunch

So:

• baru = just did it
• sedang = am doing it

Both can refer to a completed lunch, but the nuance is different.

• Saya baru makan siang = I just had lunch
  This emphasizes that it happened very recently.

• Saya sudah makan siang = I already had lunch
  This emphasizes completion, not necessarily recency.

So if someone offers you food and you want to say you already ate, Saya sudah makan siang is very common. If you want to stress that you ate only a moment ago, Saya baru makan siang fits better.

Yes.

• Saya is neutral and polite
• Aku is more casual and personal

So:

• Saya baru makan siang = neutral / polite
• Aku baru makan siang = casual

A learner should usually start with saya in general situations, then use aku with friends, family, or in informal contexts.

Sometimes, yes, especially in conversation when the subject is already clear.

For example, if someone asks:

• Sudah makan siang? = Have you had lunch?

You could reply:

• Baru makan siang. = Just had lunch.

Indonesian often drops subjects when the meaning is obvious from context. But including saya is still completely correct.

Yes, absolutely.

Baru saja also means just, and it often sounds a bit more explicit or slightly more natural in some contexts.

So these are both correct:

• Saya baru makan siang
• Saya baru saja makan siang

The second one can feel a little fuller, like I’ve just had lunch.

You would usually say:

Saya belum makan siang.

The key word is belum, which means not yet.

This is much more natural than trying to negate baru directly.

So compare:

• Saya baru makan siang = I just had lunch
• Saya sudah makan siang = I already had lunch
• Saya belum makan siang = I haven’t had lunch yet

In this sentence, it functions as part of the predicate, so you can think of it as a verb phrase meaning have lunch.

But in other contexts, makan siang can also act more like a noun phrase meaning lunch.

For example:

• Saya baru makan siang = I just had lunch
• Makan siang saya terlambat = My lunch was late

So the exact role depends on the sentence, but in your example it is best understood as the action of having lunch.

Saya baru makan siang is generally neutral. It is polite enough for many everyday situations and does not sound especially formal.

If you want a more formal style, Indonesian might use words like telah in some contexts, but in everyday speech saya baru makan siang is very normal.

If you want a more casual version, you could say:

• Aku baru makan siang.