صاحبتي قالت لي: عقبالك.

صاحبتي means my female friend.

It breaks down like this:

• صاحبة = female friend / companion
• -ي = my

In natural Egyptian speech, it often sounds shortened, something like saḥbti.

Yes. In Egyptian Arabic, صاحبتي can mean either:

• my female friend
• my girlfriend

Context tells you which one is meant. If nothing romantic is suggested, learners usually translate it as my female friend.

Because the subject, صاحبتي, is feminine.

In the past tense:

• قال = he said
• قالت = she said

So صاحبتي قالت means my female friend said.

Because Arabic commonly says said to me.

• لـ = to
• ي = me / my
• لي = to me

So قالت لي literally means she said to me.

This is very normal Arabic structure. English says she told me or she said to me, and Arabic often uses the equivalent of said to me.

Because in casual Egyptian writing, people often attach the words together the way they sound in speech.

So these are both common:

• قالت لي
• قالتلي

They mean the same thing. In fast speech, it comes out as one chunk, roughly ʔāletli.

عقبالك is a very common Egyptian expression used after a happy event. It means something like:

• may the same happen to you soon
• your turn next
• I hope you get this too

It is more of a fixed social expression than a word-for-word sentence you should translate too literally.

The literal feeling is something like after you or next for you.

So the idea is:

• something good happened to one person
• the speaker is wishing that the same good thing will happen to the listener next

That is why عقبالك is often best learned as a set phrase.

No. It is very common with weddings and engagements, but not limited to them.

People can say عقبالك for other happy milestones too, such as:

• graduation
• a new job
• success in exams
• having a baby
• travel
• moving into a new home

The shared idea is: I hope you have the same good fortune soon.

Yes, in pronunciation it does.

Commonly:

• to a man: عقبالك pronounced roughly ʿoʔbālak
• to a woman: usually written the same without vowel marks, but pronounced roughly ʿoʔbālik

Because normal Arabic writing usually leaves out short vowels, the masculine and feminine forms often look identical in writing.

Because صاحبتي is more natural in everyday Egyptian speech.

Both can mean my female friend, but:

• صاحبتي = common, spoken, everyday Egyptian
• صديقتي = more formal or closer to Standard Arabic

So صاحبتي قالت لي sounds very natural in casual Egyptian.

Overall, it feels like Egyptian Arabic.

Why:

• صاحبتي is very natural in spoken Egyptian
• عقبالك is a common colloquial expression
• قالت لي is understandable in both colloquial and Standard Arabic, though in casual Egyptian writing you often see قالتلي

So the sentence is basically spoken Egyptian written in Arabic script.

You would say:

صاحبي قال لي: عقبالك

Changes:

• صاحبي = my male friend or my boyfriend
• قال = he said

So:

• صاحبتي قالت لي = my female friend said to me
• صاحبي قال لي = my male friend said to me