الشباب هون.

In Levantine Arabic, the present-tense verb to be is usually omitted. So الشباب هون literally looks like the guys here, but it naturally means the guys are here.

This is very normal in Arabic. If you wanted a past meaning, you would use a verb, for example الشباب كانوا هون = the guys were here.

الشباب is the plural of شاب, which means young man. Depending on context, الشباب can mean:

• the young men
• the youth
• the guys
• sometimes the boys in casual speech

In everyday Levantine, it often sounds very natural as the guys when talking about a group of men or a familiar group.

الـ is the Arabic definite article, meaning the.

So:

• شباب = young men / guys in a general or indefinite sense
• الشباب = the young men / the guys, meaning a specific group already known from context

In الشباب هون, the speaker is talking about a particular group: the guys are here.

A common Levantine-style pronunciation is roughly:

ish-shabāb hōn
or
esh-shabāb hōn

A few notes:

• هون sounds like hoon with a long oo
• in الشباب, the ل of الـ is not pronounced normally, because ش is a sun letter
• so instead of el-shabāb, you get something like esh-shabāb or ish-shabāb

Regional pronunciation varies, so you may hear slightly different vowels in the article.

Because ش is one of the sun letters. When الـ comes before a sun letter, the ل assimilates to the next consonant.

So:

• written: الشباب
• pronounced: ash-shabāb / esh-shabāb / ish-shabāb depending on style and region

This is a spelling-pronunciation pattern you will see a lot in Arabic.

They both mean here, but they belong to different registers:

• هون = common in Levantine colloquial Arabic
• هنا = Standard Arabic, and also understood in speech

So الشباب هون is a clearly Levantine way to say it.
In Standard Arabic, you would more likely see الشباب هنا.

Yes. Arabic word order is flexible, and both can work.

The difference is mostly about emphasis:

• الشباب هون = neutral statement, the guys are here
• هون الشباب = puts more focus on here, something like the guys are here or here are the guys

So the original order is very natural, but the reversed order is also possible in the right context.

No. الشباب هون is already a complete and natural sentence.

But you can expand it:

• الشباب موجودين هون = the guys are here / present here
  This sounds a bit more explicit.

A pronoun like هنّي can also appear for emphasis in some speech, but it is not necessary in a basic sentence like this.

It is colloquial Levantine Arabic, mainly because of هون.

A more formal or Standard Arabic version would be:

الشباب هنا

The overall sentence structure is similar, but the word هون is what makes it sound specifically Levantine.

Usually الشباب is masculine and most naturally refers to young men or guys. It can sometimes refer more loosely to young people in a general social sense, but its basic form is masculine.

If you were talking about a group of girls, you would normally use a different word, such as الصبايا in Levantine.