مهم نروح الحديقة بدري يوم الجمعة، عشان بالليل بتبقى زحمة.

Yes—Egyptian Arabic often leaves out the present-tense verb to be.

So مهم literally means important, but here it functions like:

• It’s important
• It’s important that...

Arabic also does not need a dummy subject like English it in it’s important. So:

• مهم نروح... = It’s important that we go...

This is a very common learner question.

In Egyptian Arabic, the prefix بـ on the present tense often marks a normal present or habitual action:

• بنروح = we go / we usually go

But after words like مهم (important), Arabic often uses the bare imperfect without بـ:

• نروح = that we go / for us to go / we should go

So here:

• مهم نروح الحديقة بدري
  means something like
• It’s important that we go to the park early

If you said مهم بنروح..., it would sound off in this context.

Yes. That is also natural.

• مهم نروح...
• مهم إننا نروح...

Both can work. The version with إننا is a bit more explicit, like It’s important that we... The version without it is very common in speech and sounds lighter.

الحديقة means the park or the garden.

It is a standard word and is also used in Egyptian Arabic. In everyday speech, pronunciation may sound a bit different from the spelling, especially because ق is often pronounced as a glottal stop in Cairene Egyptian.

So الحديقة may sound roughly like:

• el-ḥadī’a / el-ḥadīʔa

But the meaning is simply the park here.

بدري means early.

Examples:

• جيت بدري = I came early
• نروح بدري = we go early

In the sentence:

• نروح الحديقة بدري = go to the park early

It’s a very common Egyptian Arabic word.

Because Arabic often uses time expressions without a separate preposition where English would use on.

So:

• يوم الجمعة = on Friday
• literally: the day of Friday

In everyday Egyptian, you may also hear just:

• الجمعة = Friday / on Friday

So all of these can be natural depending on context.

Here عشان means because.

So:

• عشان بالليل بتبقى زحمة = because at night it gets crowded

Very importantly, عشان is a flexible word in Egyptian Arabic. It can also mean:

• because
• so that
• for
• for the sake of

The exact meaning depends on context. In this sentence, because is the right reading.

بالليل means at night or sometimes in the evening, depending on context.

It is made from:

• بـ = a preposition here
• الليل = the night

So literally it is something like in the night / at night.

This pattern is very common in Egyptian Arabic:

• بالليل = at night
• بالنهار = in the daytime
• بالصيف = in the summer

بتبقى comes from the verb يبقى.

In Egyptian Arabic, يبقى can mean things like:

• be
• become
• remain
• end up

In this sentence, بتبقى زحمة means:

• it gets crowded
• it is crowded

The بـ here suggests a usual or repeated situation, not just one single future event. So the idea is:

• at night, it tends to be crowded
• at night, it gets crowded

Because the implied subject is likely something feminine, even though it is not stated directly.

The most natural understood subject is probably:

• الحديقة = the park
  which is feminine in Arabic

So the fuller idea is something like:

• عشان الحديقة بالليل بتبقى زحمة
  = because the park gets crowded at night

Arabic verbs still show agreement even when the subject is left understood.

It is originally a noun meaning something like crowding, traffic, or congestion, but in Egyptian Arabic it is very often used like an adjective/predicate meaning:

• crowded
• busy
• packed

So:

• المكان زحمة = the place is crowded
• الشارع زحمة = the street is crowded / there’s traffic

In your sentence, زحمة is best understood as:

• crowded

Several parts are strongly colloquial/Egyptian:

• نروح instead of a more formal verb like نذهب
• بدري = colloquial early
• عشان = very common Egyptian because / so that
• بتبقى = colloquial Egyptian usage of يبقى
• زحمة used this way is very common in speech

So even if some individual words are understandable across Arabic varieties, the overall sentence clearly sounds like spoken Egyptian Arabic rather than formal Modern Standard Arabic.

A broad Egyptian-style pronunciation would be something like:

• mohimm nirūḥ il-ḥadī’a badri yōm il-gomʿa, ʿashān bil-lēl bitib’a zaḥma

A few useful pronunciation notes:

• الجمعة is commonly pronounced il-gomʿa
• ق in حديقة is often pronounced as a glottal stop in Egyptian speech
• عشان is usually pronounced ʿashān

You do not need perfect pronunciation right away, but recognizing these spoken forms is very helpful.