لما توصل صديقتي، منروح نشرب قهوة.

Because Arabic commonly uses the imperfect verb after time words like لما for future events.

So:

• لما توصل صديقتي = when my friend arrives
• even though the arrival has not happened yet

This is very normal in Levantine.

In Levantine, the b- form often marks ordinary present or habitual actions. But in time clauses and future-like sequences, speakers often use the bare imperfect instead.

So لما توصل sounds natural for when she arrives.

Likewise, after another verb, a bare imperfect is also common in purpose-like phrases such as منروح نشرب = we go drink / we go to drink.

In the imperfect, تـ can mark more than one thing. It can mean:

• you (second person)
• she (third person feminine singular)

Here the subject is صديقتي = my female friend, so توصل means she arrives.

Context tells you which meaning is intended.

Yes. صديقة is a feminine noun, so صديقتي means my female friend.

If you meant my male friend, you would use صديقي.

Because the base word is صديقة. That final ة is the feminine ending. When you add a suffix like -ي for my, the ة shows up as -ت-.

So:

• صديقة = female friend
• صديقتي = my female friend

This is a very common pattern in Arabic.

منروح is the normal Levantine colloquial form for we go.

A native English speaker often notices this because in Modern Standard Arabic you expect نروح or more formally نذهب. In Levantine, first-person plural imperfect verbs commonly begin with منـ:

• منروح = we go
• منشرب = we drink
• منعرف = we know

So منروح is a dialect feature.

This is a very common Arabic structure. After a verb of movement like go, another verb can come directly to express purpose.

So:

• منروح نشرب قهوة
• literally: we go drink coffee
• natural English: we go have coffee or we go to drink coffee

English usually needs to here, but Arabic often does not.

Arabic does not use an indefinite article like a/an. A bare noun can be indefinite by itself.

So قهوة here can mean:

• coffee
• some coffee
• a coffee

depending on context.

Also, نشرب قهوة is a very natural way to say drink/have coffee.

Yes, that is possible.

The sentence you were given uses a very natural verb-first order:

• لما توصل صديقتي

You can also put the subject first:

• لما صديقتي توصل

Both are understandable. The verb-first version is especially common and natural in Arabic.

A rough Levantine pronunciation would be:

lamma twasal ṣadīʔti, mnrūḥ nishrab ʔahwe

A few notes:

• قهوة is often pronounced ʔahwe, ahwe, or qahwe, depending on region
• منروح is usually said smoothly as mnrūḥ
• صديقتي is often pronounced something like ṣadīʔti in many areas

Yes, this is clearly colloquial Levantine.

Some clues are:

• منروح for we go
• the everyday spoken flow of the sentence
• the conversational use of لما

A more Standard Arabic version might be:

عندما تصل صديقتي، نذهب لنشرب قهوة.

But the original sentence is the natural spoken Levantine way to say it.