اذا ضاع المستند، دوري عليه بالمجلد الكبير قبل ما تسالي المديرة.

It is speaking to one woman. The clues are دوري and تسألي/تسالي, which are feminine singular forms in Levantine.

Compare:

• to a woman: دوّري عليه قبل ما تسألي
• to a man: دوّر عليه قبل ما تسأل

Here دوري means look for or search for.

It is the feminine singular imperative of دوّر = to look for / to search. In fuller spelling, many people would write it as دوّري. The final -ي marks that the command is being given to a woman.

Because in Levantine, the verb دوّر usually goes with على when it means look for.

So:

• دوّر على الشي = look for something
• دوّري عليه = look for it

Literally عليه means on it / on him, but with دوّر على the natural English meaning is for it.

Because it refers back to المستند, and مستند is a masculine noun.

So:

• المستند ... دوري عليه = the document ... look for it
• if the noun were feminine, you would use عليها

For example:

• الورقة ... دوري عليها = the paper ... look for it

This is very normal in Arabic. After إذا, Arabic often uses a past form to talk about a future or general condition.

So إذا ضاع المستند does not have to mean only if the document got lost in a strict past sense. In context, it means something like:

• if the document gets lost
• if the document is missing

That past form after إذا is a common Arabic pattern.

Because إذا is usually used for a realistic or possible condition.

Here the speaker is giving a practical instruction: if this happens, do that.

Very roughly:

• إذا = if/when this actually happens
• لو = if, in a more hypothetical or unreal sense

So إذا fits better in this sentence.

قبل ما means before.

So:

• قبل ما تسألي المديرة = before you ask the manager

The ما here is part of a very common spoken pattern. It is not a negation in this sentence.

It is an informal colloquial spelling, but many learners will find تسألي clearer.

The verb comes from سأل = to ask, so a more careful spelling is:

• تسألي

In casual writing, people often simplify hamza spelling, so you may see:

• تسألي
• تسالي

In speech, it would normally sound like tisʔali or close to that, with a little stop sound for the hamza.

بالمجلد الكبير means in the big folder.

In Levantine, بـ often covers meanings like:

• in
• at
• inside
• sometimes even with

So بالمجلد is completely natural for in the folder. You do not always need في in spoken Arabic.

They are understandable, but they sound a bit formal or office-like.

• المستند = document, fairly formal
• المجلد = folder / volume / directory, also fairly formal

In everyday speech, many Levantine speakers might use words like:

• ورقة for paper/document, depending on context
• ملف or even فولدر for folder

So the sentence sounds like a mix of colloquial grammar and more formal vocabulary.

It is mixed, which is very common in real life.

The clearly colloquial parts are things like:

• دوري عليه
• قبل ما تسألي

The more formal or Standard-Arabic-like vocabulary is:

• المستند
• المجلد

This kind of mix is especially common in workplaces, schools, and semi-formal conversation.

A natural Levantine-style pronunciation could be:

iza ḍāʿ il-mustanad, dawwri ʿalēh bil-mjallad il-kbīr abel ma tisʔali l-mudīre

A few notes:

• دوّري is pronounced dawwri
• عليه here sounds like ʿalēh
• قبل ما is often said as abel ma or ʔabel ma
• تسألي includes a hamza sound: tisʔali