Saya lupa menyalakan sein dan tidak sempat melihat spion ketika mau belok.

Menyalakan is the active verb form meaning to turn on or to switch on.

• nyala = to be on / to light up / lit
• nyalakan = turn it on! (often imperative, depending on context)
• menyalakan = to turn on (active verb used in a sentence)

In this sentence, lupa menyalakan sein means forgot to turn on the turn signal.

The prefix meN- often marks an active verb. Because the base is nyala, it becomes menyalakan.

Sein means turn signal or indicator on a vehicle.

It is very common in everyday Indonesian, especially in speech. It comes from Dutch influence. In practice, many Indonesians say lampu sein or just sein.

So:

• menyalakan sein = turn on the turn signal
• lupa menyalakan sein = forgot to use the turn signal

Even if it is not the most textbook-native-looking word, it is absolutely normal and widely understood.

In Indonesian, possession is often left unstated when it is obvious from context.

Here, melihat spion naturally means look at the mirror of the vehicle the speaker is using. It does not need spion saya unless the speaker wants to emphasize my mirror.

So:

• melihat spion = look at the mirror
• melihat spion saya = look at my mirror

The shorter version is more natural here.

Spion means a vehicle mirror, usually a rear-view mirror or side mirror, depending on context.

In driving contexts, melihat spion usually means checking the mirror before changing direction or turning.

Like sein, spion is a very common everyday word in Indonesian.

Yes. Tidak sempat means didn't have time to, didn't get the chance to, or wasn't able to in time.

In this sentence:

• tidak sempat melihat spion = did not have time to check the mirror

It often suggests that something happened too quickly, or the person failed to do something before the next action.

This is slightly different from simply tidak melihat spion:

• tidak melihat spion = did not look at the mirror
• tidak sempat melihat spion = did not get a chance to look at the mirror

So tidak sempat adds the idea of insufficient time or opportunity.

Ketika mau belok means something like when I was about to turn or as I was going to turn.

• ketika = when
• mau belok = about to turn / going to turn

This gives a more immediate feeling: the speaker forgot the signal and did not check the mirror at the moment they were about to turn.

By contrast:

• sebelum belok = before turning

That is also possible, but it is a bit more neutral and less tied to the precise moment.

So:

• ketika mau belok = when about to turn
• sebelum belok = before turning

Both can work, but ketika mau belok feels more like a real driving moment.

Not exactly. Mau can mean want to, but in many contexts it also means be about to or going to.

Here, mau belok does not usually mean wanted to turn in the sense of desire. It means:

• was about to turn
• was going to turn

This use of mau is very common in Indonesian.

For example:

• Hujan mau turun. = It is about to rain.
• Saya mau pergi. = I am going / I am about to leave / I want to go, depending on context.

So context decides whether mau means want or be about to.

Because Indonesian often omits repeated subjects when they are already clear.

The full version could be:

• Saya lupa menyalakan sein dan saya tidak sempat melihat spion ketika mau belok.

But repeating saya is unnecessary. Once the subject is established, Indonesian often leaves it out in the next clause if there is no confusion.

This makes the sentence sound more natural.

Yes. Lupa is commonly followed by a verb to mean forget to do something.

Examples:

• Saya lupa makan. = I forgot to eat.
• Dia lupa membawa dompet. = He forgot to bring his wallet.
• Saya lupa menyalakan sein. = I forgot to turn on the turn signal.

So lupa + verb is a very normal pattern.

Yes, this sentence is natural and understandable. But in everyday speech, people might say a more casual version such as:

• Saya lupa nyalain sein dan nggak sempat lihat spion waktu mau belok.

Differences:

• menyalakan → nyalain (more casual)
• tidak → nggak (colloquial)
• melihat → lihat (more casual)
• ketika → waktu (more common in conversation)

The original sentence is perfectly good and slightly more standard.

Both relate to turning, but belok is much more common in everyday use.

• belok = turn
• berbelok = to make a turn / to turn, but it sounds more formal or literary in many contexts

So:

• mau belok = natural, common
• mau berbelok = possible, but less common in casual speech

In driving situations, belok is usually the normal choice.

Word-for-word, you might be tempted to do that, but it is not natural English.

A better English rendering would be:

• I forgot to turn on the indicator and didn’t have time to check the mirror when I was about to turn.

This shows an important point: Indonesian often uses verb sequences that should be translated into more natural English patterns, such as:

• lupa + verb → forgot to + verb
• sempat + verb → have time/chance to + verb

So it is better to understand the structure as natural Indonesian rather than translate each word mechanically.