بالمكتب القديم كان في طوابع ومغلفات بالجارور اللي تحت.

In Levantine, في can mean there is / there are in addition to its basic meaning in.
So:

• في طوابع = there are stamps
• كان في طوابع = there were stamps

Here, كان puts the existential idea into the past. So كان في طوابع ومغلفات means there were stamps and envelopes.

That is very normal in this kind of existential sentence. In Levantine, when you say كان في... meaning there was/there were..., كان often stays in the default masculine singular form, even if what follows is plural.

So:

• كان في كتاب = there was a book
• كان في كتب = there were books

This is similar to how English uses there was / there were, except Levantine often keeps كان singular in this structure.

The prefix بـ is a very common preposition in Levantine. It can mean things like:

• in
• at
• sometimes on, depending on context

So here:

• بالمكتب القديم = in/at the old desk
• بالجارور = in the drawer

It is the dialect equivalent of a lot of everyday location phrases.

It can mean either, depending on context. But in this sentence, desk is the more likely meaning, because the sentence later mentions the drawer underneath.

So a learner should notice that مكتب is one of those words whose meaning depends heavily on context:

• مكتب = desk
• مكتب = office

Here, desk fits best.

Because Arabic adjectives match the noun in definiteness.

If the noun is definite, the adjective must also be definite:

• مكتب قديم = an old desk
• المكتب القديم = the old desk

So القديم is not separate from المكتب in meaning; it is the adjective old, and it has to match the desk.

اللي is a very common Levantine word meaning that, which, or the one that.
تحت means under or below.

So:

• الجارور اللي تحت literally = the drawer that is below
• natural English = the bottom drawer or the lower drawer

This is a very common spoken way to describe something, and it sounds much more conversational than a more formal adjective like السفلي.

Arabic often puts the place or time first to set the scene. So starting with بالمكتب القديم feels very natural.

It is like saying:

• As for the old desk...
• In the old desk...

Then the speaker gives the information: there were stamps and envelopes in the bottom drawer.

So the word order is not strange; it is a very normal Arabic way to present information.

Because they do not have الـ. That makes them stamps and envelopes, not the stamps and the envelopes.

After في or كان في in an existential sentence, indefinite nouns are extremely common:

• في مي = there is water
• كان في ناس = there were people
• كان في طوابع ومغلفات = there were stamps and envelopes

This matches English pretty well, because English also usually uses indefinite nouns after there is / there are.

It is understandable, but it sounds a bit closer to formal Arabic than some everyday Levantine choices. Many speakers in the Levant would more commonly say ظروف for envelopes.

So:

• مغلفات = understandable, somewhat formal or neutral
• ظروف = very common everyday word

A learner should recognize مغلفات, but also know that ظروف is very frequent in real speech.

جارور means drawer, and it is a very common word in Levantine.
You may also hear درج in some places for drawer.

So:

• جارور = drawer
• الجارور اللي تحت = the bottom drawer

Both vocabulary and pronunciation can vary a bit by region, but جارور is a very useful word to know.

A simple transliteration would be:

bil-maktab il-adīm kān fī ṭawābiʿ w-mġallafāt bil-jārūr illi taḥt

A few helpful notes:

• و attaches to the next word, so ومغلفات is read as w-mġallafāt
• اللي is usually pronounced illi or yalli, depending on region
• بـ is often pronounced bi-

So in natural speech, it flows together quite smoothly.

Yes. The exact wording can change while keeping the same meaning. For example, a speaker might use different everyday vocabulary:

• بالمكتب القديم كان في طوابع وظروف بالجارور اللي تحت
• كان في طوابع ومغلفات بالجارور اللي تحت بالمكتب القديم

The original sentence is perfectly understandable, but spoken Levantine often allows a lot of flexibility in both word choice and word order.