بالبناية في شقتين، وحدة صغيرة ووحدة كبيرة.

بالبناية means in the building or in this building.

It is made of:

• بـ = a preposition that often means in / at / by
• ال = the
• بناية = building

So بالبناية is literally in the building.

Starting with the location is very natural in Levantine. It sets the scene first: As for the building, ... / In the building, ...

Yes, but this في is doing a different job.

In Levantine, في can mean:

1. in
2. there is / there are

Here it is the existential في, meaning there is / there are.

So:

• بالبناية = in the building
• في شقتين = there are two apartments

Together:

• بالبناية في شقتين = In the building, there are two apartments

So the first part gives the location, and the second part tells you what exists there.

Because Arabic has a special form for two, called the dual.

• شقة = apartment
• شقتين = two apartments

A native English speaker often expects two + plural, but Arabic often uses a special dual form instead.

In Levantine, the dual commonly ends in -ين / -ēn, so شقتين is the normal dialect form.

Compare:

• شقة = one apartment
• شقتين = two apartments
• شقق = apartments (three or more, or plural in general)

Because this sentence is in Levantine Arabic, not Modern Standard Arabic.

In MSA, you might expect:

• شقتان in some contexts
• شقتين in others

But in Levantine, the dual is usually simplified to -ين, so شقتين is the normal everyday form.

So this is one of those places where dialect and MSA differ.

It literally means:

• one small one
• and one big one

More naturally in English:

• one is small and one is big
• one small and one big

Here وحدة means one in the feminine form, because it refers back to شقة, which is a feminine noun.

So the sentence is splitting the two apartments into two items:

• one small
• one big

In Levantine, واحدة is often pronounced and written in a shortened colloquial way as وحدة.

So:

• واحدة = the fuller/formal spelling
• وحدة = very common colloquial spelling/pronunciation in dialect writing

Both point to the feminine form of one, but وحدة looks more natural in everyday Levantine-style writing.

Because they refer to شقة, and شقة is feminine.

Arabic adjectives must agree with the noun they describe. So:

• شقة صغيرة = a small apartment
• شقة كبيرة = a big apartment

Even though شقة is not repeated after وحدة, it is still understood. So the adjectives stay feminine:

• وحدة صغيرة
• وحدة كبيرة

Because once شقتين has already been mentioned, Arabic can leave the noun understood.

So instead of saying:

• شقة صغيرة وشقة كبيرة

it can say:

• وحدة صغيرة ووحدة كبيرة

This is similar to English:

• There are two apartments: one small and one big.

So وحدة works a bit like one in English, standing in for one apartment.

Because they play different roles in the sentence.

• البناية = the building
  This is a specific, identifiable building.

• شقتين = two apartments
  These are being introduced as new information.

In existential sentences with في meaning there is/are, the thing that exists is very often indefinite in Arabic. That is why شقتين appears without ال.

So the pattern is very natural:

• In the building, there are two apartments

Yes. Levantine word order is flexible.

This version:

• بالبناية في شقتين

puts the location first, which sounds natural and helps set the scene.

A speaker could also say something like:

• في شقتين بالبناية

which also means There are two apartments in the building.

The version you have is especially good for emphasizing the place first:

• In the building, there are two apartments.

A rough pronunciation is:

bil-bināye fī sha'tēn, waḥde zġīre w waḥde kbīre

A few notes:

• و is often pronounced just like w = and
• وحدة here sounds like waḥde
• كبيرة sounds like kbīre
• صغيرة sounds like zġīre in many Levantine varieties

Pronunciation differs a bit from region to region, but that rough version will help you recognize the sentence.