Learn Hardcore Malay: Saya hilang tumpuan apabila saya lapar.

Leaving out the second saya (apabila lapar) is also natural, especially in speech or informal writing. The subject (saya) is understood from context, so you don’t have to repeat it.

Meaning-wise, there is no real difference here; both can mean “I lose focus when I’m hungry.”

Can I put apabila saya lapar at the beginning of the sentence?

Yes. These two are both natural and mean the same thing:

Saya hilang tumpuan apabila saya lapar.
Apabila saya lapar, saya hilang tumpuan.

Putting apabila saya lapar first gives a bit more emphasis to the condition/time (“when I’m hungry”), but it’s only a small nuance. A comma after the first clause is common in writing: Apabila saya lapar, saya hilang tumpuan.

What’s the difference between apabila, bila, ketika, and kalau here?

All of these can relate to time, but they’re not identical:

apabila – “when” (time-based), rather formal/standard.
- Saya hilang tumpuan apabila saya lapar.
bila – “when”, very common in speech, also used for questions.
- Saya hilang tumpuan bila saya lapar. (more conversational)
ketika – “when / at the time when / while”, often in written or narrative style.
- Saya hilang tumpuan ketika saya lapar. (sounds a bit more literary)
kalau – mainly “if”, i.e. a condition, not just time.
- Saya hilang tumpuan kalau saya lapar. = I lose focus if I’m hungry (not strictly every time; it’s a condition).

In your original sentence, apabila is a good neutral–formal choice for “when (whenever)”.

What does hilang tumpuan literally mean, and how is it formed?

Literally:

hilang = lost / gone / to disappear
tumpuan = focus, concentration, attention (a noun from the root tumpu, “to support / to focus on”)

So hilang tumpuan is literally “(my) focus is lost / disappears”, which corresponds well to English “lose focus / lose concentration.”

Some close alternatives:

hilang fokus – very common, a bit more casual (using the loanword fokus).
kehilangan tumpuan – more formal, “to lose one’s focus”.
tak boleh fokus – “can’t focus”.

All of these can be used in everyday language depending on style and context.

What’s the difference between hilang tumpuan and kehilangan tumpuan?

Both can translate as “lose focus”, but the structure is slightly different:

hilang tumpuan
- hilang works like “to be lost / to disappear”.
- Often used in fixed expressions: hilang tumpuan, hilang semangat, etc.
- Very natural in speech and writing.
kehilangan tumpuan
- ke-…-an on hilang makes kehilangan, which means “to suffer the loss of / to lose (something)”.
- Sounds a bit more formal or written, and often used in more serious or descriptive contexts.

In everyday conversation, hilang tumpuan and hilang fokus are probably more common.

I’ve seen Dompet saya hilang and Saya kehilangan dompet. Can I say Saya hilang dompet?

Normally, no — Saya hilang dompet is unnatural for most speakers.

Standard patterns:

Dompet saya hilang.
= My wallet is missing / has gone.
Subject is dompet (the thing that disappeared).
Saya kehilangan dompet.
= I lost my wallet.
Subject is saya (the person who suffered the loss).

With hilang tumpuan, you have a fixed expression, so Saya hilang tumpuan is accepted as “I lose focus”, but for concrete objects (wallet, keys, phone) you should use the two patterns above, not Saya hilang dompet.

What exactly does tumpuan mean? Can I just use fokus instead?

tumpuan is a noun from tumpu and means:

focus, concentration, attention
sometimes also “centre (of attention)” or “target/focal point”

In your sentence, it’s “focus / concentration”.

You can often replace it with fokus, which is a very common loanword from English:

Saya hilang tumpuan apabila saya lapar.
Saya hilang fokus apabila saya lapar.

Both are natural. tumpuan can sound slightly more formal or standard-Malay; fokus is very widely used in everyday conversation and writing.

In saya lapar, where is the word “am”? Why isn’t there something like “saya adalah lapar”?

Malay normally has no “to be” verb (am / is / are) in the present tense.

So:

saya lapar = I am hungry
dia penat = he/she is tired
makanan ini sedap = this food is delicious

You usually do not say saya adalah lapar.
adalah is used mainly before nouns in some formal/written structures (e.g. Dia adalah seorang guru – He is a teacher), and even there it’s often optional.

For states and adjectives like hungry, tired, busy, happy, you just put the pronoun + adjective:

saya lapar – I am hungry
saya penat – I am tired
saya sibuk – I am busy

Does this sentence mean a general habit (“whenever I’m hungry”), or can it also describe one specific time?

Saya hilang tumpuan apabila saya lapar most naturally suggests a general tendency / habit:

“Whenever I’m hungry, I lose focus.”

To talk about one specific past event, Malay usually adds a time word or aspect marker:

Tadi saya hilang tumpuan apabila saya lapar.
Earlier, I lost focus when I was hungry.
Semalam saya hilang tumpuan apabila saya lapar.
Yesterday I lost focus when I was hungry.

For future:

Saya akan hilang tumpuan apabila saya lapar nanti.
I will lose focus when I’m hungry (later).

Without extra time words, the sentence is read as generally true about you.

Is this sentence formal or informal? How would people say it in casual conversation?

Saya hilang tumpuan apabila saya lapar is neutral–standard. It works in writing and in polite speech.

In casual conversation, people often:

use aku instead of saya (with friends, same age)
use bila instead of apabila
use fokus or tak boleh fokus instead of tumpuan

Examples:

Aku hilang fokus bila aku lapar.
Aku tak boleh fokus bila aku lapar.
Bila aku lapar, aku memang tak boleh fokus.

All of these are very natural in everyday spoken Malay.

Can I drop saya completely and just say Hilang tumpuan bila lapar?

Yes, in informal contexts you can shorten it like that:

Hilang tumpuan bila lapar.

This sounds like a casual note, a social media post, or speech, where the subject “I” is obvious from context. It’s grammatically looser but very common in real life.

More neutral but still short:

Hilang tumpuan apabila lapar.
(still a bit more standard because of apabila)

How do I pronounce the words in this sentence correctly?

Rough breakdown (stressed fairly evenly; Malay doesn’t have strong stress like English):

Saya – sa-ya
- sa like sa in salsa
- ya like ya in yard (but shorter)
hilang – hi-lang
- hi like hee (short)
- lang with ng as in singer (one sound, not “n-g”)
tumpuan – tum-pu-an
- tum like toom
- pu like poo (short)
- an roughly like un in sun (but with a clearer “a”)
apabila – a-pa-bi-la
- all vowels are clear: a-pa-bee-la (but not long)
lapar – la-par
- la like la in lava
- par like par in partner (no strong r-roll in most Malaysian accents)

Whole sentence, smoothly:
Sa-ya hi-lang tum-pu-an a-pa-bi-la sa-ya la-par.