الليلة نشغل الغسالة.

In this sentence, اللَّيْلَةَ is being used as a time expression, so it means tonight / this evening.

Literally, the word is related to night, but Arabic often uses nouns this way as adverbs of time. So:

• اللَّيْلَةَ = tonight
• not necessarily the night in a literal noun sense

In grammar terms, it is a ظرف زمان (adverbial expression of time), which is why it is normally in the accusative.

Because the ل in لَيْلَة is a sun letter.

When the definite article الـ comes before a sun letter, the l of the article assimilates to the next consonant. So:

• underlying form: ال + ليلة
• pronounced: اللَّيْلَة

That is why you see a shadda on ل and pronounce it like a doubled l sound.

Arabic often puts time expressions first to set the scene or frame the sentence.

So:

• اللَّيْلَةَ نُشَغِّلُ الغَسَّالَةَ = Tonight, we turn on the washing machine

But you could also say:

• نُشَغِّلُ الغَسَّالَةَ اللَّيْلَةَ

Both are grammatical. Putting اللَّيْلَةَ first gives a little more emphasis to when it happens.

نُشَغِّلُ means we operate, we run, or we turn on.

Here it comes from the verb شَغَّلَ:

• root: ش غ ل
• basic idea: making something work, run, or operate

So with a machine, نُشَغِّلُ usually means:

• we turn it on
• we run it

A useful contrast:

• نُشَغِّلُ الغسالة = we turn on / run the washing machine
• نَغْسِلُ = we wash

So the verb is not about washing itself; it is about operating the machine.

In the Arabic imperfect/present tense, the beginning of the verb shows the subject.

Here, نـ marks first person plural, so:

• نُشَغِّلُ = we turn on / we run

That is why Arabic does not need a separate word for we here. The verb already contains that meaning.

If you wanted to add we explicitly for emphasis, you could say:

• نحن نُشَغِّلُ الغسالة الليلة

But normally نحن is unnecessary.

Formally, it is the imperfect verb form, which can refer to present or future, depending on context.

In this sentence, اللَّيْلَةَ makes the meaning future-like:

• Tonight we will turn on the washing machine
• or Tonight we turn on the washing machine

So even without a special future marker, the time word makes the meaning clear.

If you wanted to make the future more explicit, you could say:

• سَنُشَغِّلُ الغسالة الليلة
• سوف نُشَغِّلُ الغسالة الليلة

Both mean we will turn on the washing machine tonight.

As written, it is most naturally a statement:

• Tonight we turn on / will turn on the washing machine

If you want Let’s turn on the washing machine tonight, MSA would usually say something like:

• هَيّا نُشَغِّلُ الغسالة الليلة
• or more formally لِنُشَغِّلِ الغسالة الليلة

So نُشَغِّلُ by itself is not the normal MSA way to say let’s turn on...
It is simply we turn on / we will turn on.

الغسالة means the washing machine.

It comes from the root غ س ل, which is connected with washing. The ending ـة makes it a feminine noun, and many machine/device nouns in Arabic are feminine.

So:

• غسالة = washing machine
• الـ makes it definite: the washing machine

In context, it usually refers to a specific machine already known to the speaker and listener.

Because the sentence is talking about a specific washing machine, not just any washing machine.

So:

• غسالة = a washing machine
• الغسالة = the washing machine

In everyday context, this often means the washing machine in the house or another machine both people already know about.

A fully vowelled version is:

اللَّيْلَةَ نُشَغِّلُ الغَسَّالَةَ

Here is what the endings show:

• اللَّيْلَةَ: accusative, because it is a time expression
• نُشَغِّلُ: indicative imperfect
• الغَسَّالَةَ: accusative, because it is the direct object

In normal unvowelled writing, these short vowels are usually omitted, so learners have to infer them from grammar and context.

A careful pronunciation is roughly:

al-laylata nushagghilu al-ghassālata

If you pause at the end, it is often heard more like:

al-laylah nushagghil al-ghassālah

A few pronunciation notes:

• اللَّيْلَةَ has a doubled l
• نُشَغِّلُ has a doubled ghgh / gg sound because of the shadda
• غ is a deep, throaty sound not found in English
• الغَسَّالَةَ also has a doubled s sound

So the sentence has several places where consonant doubling matters.