يعمل المنبه.

A careful MSA pronunciation is:

yaʿmalu al-munabbihu

If fully vowelled, it is:

يَعْمَلُ المُنَبِّهُ

A few notes:

• يعمل = yaʿmalu
• المنبه = al-munabbihu
• The letter ع in يعمل is a deep throat sound with no exact English equivalent.
• In المنبه, the بّ is doubled, so you hold the b sound slightly longer.
• In normal pausal pronunciation, the final short vowels are often not pronounced, so you may hear something closer to yaʿmal al-munabbih.

Here, يعمل means works, is working, or operates.

The basic verb is عَمِلَ / يَعْمَلُ, which is related to doing or working. With a machine or device, it often means:

• to work
• to function
• to operate

So يعمل المنبه most naturally means The alarm clock works or The alarm is working.

Because Arabic verbs agree with the grammatical gender and number of the noun, not with natural gender the way English does.

المنبّه is a singular masculine noun in grammar, so the verb appears in the 3rd person masculine singular form:

• يعمل = he works / it works

In Arabic, the same verb form can mean he works or it works, depending on the noun that follows.

المنبّه usually means the alarm clock or the alarm.

It comes from the root ن ب ه, which has to do with being alert, noticing, or waking up. So منبّه is something like that which alerts/wakes.

Depending on context, it can mean:

• alarm clock
• alarm
• sometimes more generally alerting device

If you want to be very explicit, Arabic can also say ساعة منبّهة for alarm clock.

الـ is the Arabic definite article, meaning the.

So:

• منبّه = an alarm / alarm clock
• المنبّه = the alarm / the alarm clock

In this sentence, the noun is definite, so it refers to a specific alarm or alarm clock.

Both are possible, but they are structured differently.

• يعمل المنبه = a verbal sentence, starting with the verb
• المنبه يعمل = a nominal sentence, starting with the noun

In MSA, starting with the verb is very common when you are simply stating that an action happens:

• يعمل المنبه = The alarm clock works / is working

Starting with the noun can put a bit more focus on the subject:

• المنبه يعمل = The alarm clock is working

Both are correct, but يعمل المنبه is a very normal, neutral verbal-sentence pattern.

In fully vocalized MSA, the sentence is:

يَعْمَلُ المُنَبِّهُ

The endings are:

• يعملُ: final -u because it is in the indicative mood
• المنبّهُ: final -u because it is the subject and therefore nominative

So grammatically:

• يَعْمَلُ = he/it works
• المُنَبِّهُ = the alarm clock as the subject

In everyday reading, news headlines, and most unvowelled text, these endings are usually not written.

It is pronounced normally as al- here.

That is because م in المنبّه is a moon letter, not a sun letter. So the l of الـ stays pronounced:

• المنبّه = al-munabbih

Compare that with a sun-letter word like الشمس, where the l is not pronounced:

• الشمس = ash-shams

But here it stays:

• المنبّه = al-munabbih

Sometimes a learner might guess that, but يعمل المنبه more naturally means:

• The alarm works
• The alarm is working
• The alarm clock is operating

If you specifically want The alarm goes off / rings, Arabic would more naturally use a verb like:

• يَرِنُّ المنبّه = The alarm rings / is ringing
• رَنَّ المنبّه = The alarm rang

So يعمل المنبه is more about functioning, not specifically making sound.

In Arabic, every noun has a grammatical gender, and منبّه is treated as masculine.

There is not always a logical real-world reason for this from an English perspective. It is simply part of the noun's grammar. Because it is masculine singular, the verb appears as masculine singular too:

• يعمل المنبه

If the noun were feminine, the verb form would usually change accordingly.

They come from different roots:

• يعمل comes from ع م ل, a root connected with work, doing, and action
• المنبّه comes from ن ب ه, a root connected with alertness, attention, and waking up

So the sentence combines:

• a verb of working/functioning
• a noun meaning something that alerts or wakes

That is why the whole sentence means The alarm clock works.