Entah bila dia tiba.

Entah shows uncertainty, not knowing, or wondering. In this sentence, it gives the sense of:

• who knows when...
• I don’t know when...
• no idea when...

So it does not simply add information; it tells you the speaker is unsure.

Bila means when. After entah, it introduces the unknown time:

• Entah bila dia tiba = Who knows when he/she will arrive

This is a very natural pairing in Malay: entah + question word.

Examples:

• Entah siapa yang datang. = No idea who came.
• Entah di mana dia sekarang. = Who knows where he/she is now.
• Entah bila dia tiba. = Who knows when he/she arrived / will arrive.

Malay normally puts the question word at the start of that clause. So bila dia tiba is the natural order for when he/she arrives.

Structure:

• entah = marker of uncertainty
• bila dia tiba = when he/she arrives

So the whole sentence is built as:

• Entah
  • bila dia tiba

Putting dia before bila would sound unnatural in standard Malay.

Yes. Dia can mean either he or she. Malay does not usually mark gender in third-person singular pronouns.

So without context, dia could refer to:

• a man
• a woman

Context tells you which one is meant.

Malay often does not mark tense explicitly the way English does. The verb tiba can be understood from context.

Depending on the situation, Entah bila dia tiba could mean something like:

• Who knows when he/she arrived
• Who knows when he/she will arrive
• I wonder when he/she arrives

In real use, context usually makes the time clear. If the speaker wants to make the future more explicit, they might say:

• Entah bila dia akan tiba.

Here, akan makes the future meaning clearer.

Tiba means arrive. It is a fairly standard and common verb.

In this sentence:

• dia tiba = he/she arrives

It is an intransitive verb here, so it does not take a direct object.

You may also hear sampai, which can also mean arrive/reach, but tiba is perfectly natural in this sentence.

Not usually a direct question. It is more like a statement of uncertainty or a wondering remark.

So it behaves more like:

• Who knows when he’ll arrive.
• I have no idea when she arrived.

The speaker is not necessarily asking someone to answer. They are expressing that the time is unknown.

Because the sentence is usually understood as a statement, not a direct information-seeking question.

Even though it contains bila (when), the function is not really asking. It is more like commenting on uncertainty.

That said, in informal writing, some people might use a question mark if they want to reflect a more wondering tone, but a full stop is very normal.

Yes. Entahlah is very common in speech and informal writing.

The -lah here does not change the core meaning much, but it can make the sentence sound:

• more conversational
• a bit softer
• a bit more expressive

So these are both possible:

• Entah bila dia tiba.
• Entahlah bila dia tiba.

The second often sounds more natural in everyday conversation.

Usually bila is the more natural choice here.

• bila = common, everyday when
• apabila = more formal, often used in more careful or written styles

After entah, bila sounds more idiomatic:

• Entah bila dia tiba.

Using apabila is possible in some formal or literary contexts, but it is less natural for ordinary speech:

• Entah apabila dia tiba.

Most learners should treat bila as the normal choice here.