ضوء الطوارئ على وشك أن ينطفئ.

على وشك is a fixed expression meaning on the verge of, about to, or just about to.

So in this sentence, it tells you that the action is very close to happening. It is stronger and more immediate than simply using the future.

• هو على وشك أن يخرج = He is about to leave.
• ضوء الطوارئ على وشك أن ينطفئ = The emergency light is about to go out.

After على وشك, Arabic normally uses أن + imperfect verb.

So the pattern is:

على وشك أن + فعل مضارع

Examples:

• أنا على وشك أن أنام = I’m about to sleep.
• هي على وشك أن تبكي = She is about to cry.

In your sentence:

• أن ينطفئ = to go out / to switch off / to be extinguished

This is the standard structure in MSA.

ينطفئ means goes out, is extinguished, or switches off, depending on context.

It is used for things like:

• lights
• flames
• fires
• candles

So with ضوء it means the light is about to stop shining.

The verb is from انطفأ = to go out / be extinguished.

The يـ marks the imperfect verb and, here, specifically third person masculine singular.

That matches ضوء, which is grammatically masculine singular.

So:

• ضوء ... ينطفئ = the light ... goes out

If the subject were feminine singular, you would usually see تـ instead:

• النار تنطفئ = the fire is going out

Because this is an iḍāfa construction, often called a genitive construction or noun-noun phrase.

In an iḍāfa:

• the first noun does not take ال
• the second noun can be definite, and that makes the whole phrase definite

So:

• ضوء الطوارئ = the emergency light

Even though ضوء has no ال, the whole phrase is definite because الطوارئ is definite.

This is very common in Arabic:

• باب البيت = the door of the house
• مدير المدرسة = the school principal
• ضوء الطوارئ = the emergency light

It is an iḍāfa phrase:

• ضوء = light
• الطوارئ = emergency / emergencies

Literally, it is something like light of emergency, but natural English is emergency light.

In this structure:

1. the first noun (ضوء) is the thing being described
2. the second noun (الطوارئ) specifies what kind of thing it is

So Arabic often expresses what English might show with:

• of
• a compound noun
• an adjective-like noun

الطوارئ is historically a plural form, but in modern usage it often behaves like a set expression meaning emergency in institutional or practical contexts.

You see it in phrases like:

• قسم الطوارئ = emergency department
• حالة طوارئ = state of emergency
• مخرج الطوارئ = emergency exit
• ضوء الطوارئ = emergency light

So even though its form is plural, you do not need to translate it as emergencies here. In this sentence it simply functions like emergency in English compound nouns.

This is a very normal nominal sentence in Arabic.

The sentence begins with the subject/topic:

• ضوء الطوارئ

Then it gives information about it:

• على وشك أن ينطفئ

So the structure is roughly:

[subject/topic] + [comment about it]

Arabic often does this, especially when introducing what something is, is like, or is about to do.

A careful MSA pronunciation would be approximately:

ḍawʾu ṭ-ṭawāriʾ ʿalā washki ʾan yanṭafiʾ

A few pronunciation notes:

• ضوء has a hamza at the end: ḍawʾ
• الطوارئ also ends in hamza: aṭ-ṭawāriʾ
• because ط is a sun letter, ال assimilates, so you hear aṭ-ṭ..., not al-ṭ...
• ينطفئ ends with a glottal stop too: yanṭafiʾ

In normal reading without full case endings, learners often say it more simply as:

ḍawʾ aṭ-ṭawāriʾ ʿalā washk an yanṭafiʾ

If fully vocalized in careful MSA, it would be:

ضَوْءُ الطَّوَارِئِ عَلَى وَشْكِ أَنْ يَنْطَفِئَ

Why?

• ضوءُ is nominative because it is the subject/topic of the nominal sentence
• الطوارئِ is genitive because it is the second term of an iḍāfa
• وشكِ is genitive because it comes after the preposition على
• ينطفئَ is in the subjunctive after أن

Many everyday texts omit these endings, but they are useful to understand the grammar.

It usually means the action is very close and expected very soon, but it does not absolutely guarantee that it will happen.

So ضوء الطوارئ على وشك أن ينطفئ means the light is at the point where it seems likely to go out any moment.

It conveys strong immediacy:

• closer than a simple future
• similar to is about to in English

Yes, depending on nuance.

For a light, ينطفئ is very natural because it means to go out or be extinguished.

Other possibilities may exist in different contexts, for example verbs meaning:

• to turn off
• to stop working
• to lose power

But ينطفئ is a very good standard choice for a light that is about to stop shining.

Yes, very freely. It works with different persons and nouns.

Examples:

• أنا على وشك أن أغادر = I am about to leave.
• نحن على وشك أن نبدأ = We are about to begin.
• الطفل على وشك أن يبكي = The child is about to cry.
• السيارة على وشك أن تتوقف = The car is about to stop.

So your sentence follows a very useful pattern that you can reuse often: [subject] + على وشك أن + [imperfect verb]