هاي البنت اخت صديقتي.

A common Levantine-style pronunciation would be roughly:

haay il-bint ikht sadii'ti

A few notes:

• هاي = haay
• البنت is often pronounced il-bint or el-bint
• اخت may sound like ikht, ekht, or ukht depending on the local accent
• In صديقتي, many Levantine speakers pronounce ق as a glottal stop, so it sounds like sadii'ti

So the exact sound can vary a bit by country and city.

هاي means this for a feminine singular noun.

Since بنت is feminine singular, هاي is the matching form.

So:

• هاي البنت = this girl

Arabic demonstratives agree with the noun in gender and number.

Here, بنت is feminine, so you use هاي.

A common masculine equivalent in Levantine would be:

• هاد
• or هيدا in some regions

So:

• هاي البنت = this girl
• هاد الشب = this guy
• هيدا الولد = this boy in some varieties

In Arabic, especially in the present tense, sentences like this usually do not use a spoken word for is.

So:

• هاي البنت اخت صديقتي literally looks like
• this girl sister my-friend

But the meaning is:

• This girl is my friend’s sister

This is completely normal in Arabic.
If you wanted past tense, then you would use a verb such as كان.

In Levantine, when you say this + noun, the noun is very often definite.

So هاي البنت is the natural way to say:

• this girl

Literally it looks like:

• this the-girl

That may feel strange from an English point of view, but it is normal Arabic structure.

Because اخت صديقتي is a possession structure called iḍāfa.

It means:

• the sister of my friend
• or more naturally, my friend’s sister

In an iḍāfa, the first noun usually does not take ال.

So:

• اخت صديقتي = my friend’s sister not
• الاخت صديقتي

The whole phrase is still definite because صديقتي is already definite: it means my friend.

صديقتي = صديقة + ي

That means:

• صديقة = female friend
• ـي = my

So:

• صديقتي = my female friend

Also, when a suffix like ـي is added, the final ة of صديقة is pronounced as t.

That is why it sounds like:

• sadii'ti not just
• sadii'a

Yes.

صديقة is the feminine form, so صديقتي means my female friend.

If the friend were male, you would normally say:

• صديقي = my male friend

So this sentence specifically says the girl is the sister of a female friend.

That is very common in informal writing.

In careful spelling, the word is:

• أخت

But in texting, chats, and casual writing, many people simply write:

• اخت

Both mean the same thing here:

• sister

So this is mostly a spelling simplification, not a change in meaning.

Yes. بنت can mean:

• girl
• daughter
• sometimes young woman, depending on context

In this sentence, this girl is the most natural reading:

• هاي البنت = this girl

If the context were about family relationships, it could sometimes be understood differently, but here girl is the clearest meaning.

Yes. Different parts of the Levant use slightly different demonstratives and pronunciations.

For example, some speakers might say:

• هيدي البنت أخت صديقتي

This means the same thing.

You may hear:

• هاي
• هيدي
• different pronunciations of أخت
• different pronunciations of ق in صديقتي

So the sentence may sound a little different across Lebanon, Syria, Palestine, and Jordan, but the structure stays basically the same.