الذكريات دي حلوة.

A natural pronunciation is:

ez-zekrayyāt di ḥelwa

A few helpful notes:

• الـ becomes ez- here because ذ is a sun letter, so the l sound assimilates.
• In Egyptian Arabic, ذ is usually pronounced like z, not like the English th in this.
• ذكريات sounds roughly like zek-ray-YAAT.
• دي is di.
• حلوة is ḥelwa, with ḥ being a stronger, throatier h than English h.

Because in Egyptian Arabic, demonstratives like this/these often come after the noun.

So:

• الذكريات دي = these memories

This may feel backwards to an English speaker, but it is completely normal in Egyptian Arabic.
Literally, it looks like the memories these, but the real meaning is just these memories.

Here, دي is the demonstrative meaning this/these.

In this sentence, it helps point to the noun:

• الذكريات دي = these memories

So دي is not a separate pronoun like she or it here. It is functioning as a demonstrative attached to the noun phrase.

This is one of the most important grammar patterns in Arabic.

Even though الذكريات is plural in meaning, it is a non-human plural. In Arabic, non-human plurals are very often treated grammatically as feminine singular.

That is why you get:

• دي instead of a masculine singular form
• حلوة in the feminine singular form

So the grammar is singular feminine, even though the meaning is plural in English.

For the same reason: الذكريات is a non-human plural, and non-human plurals commonly take feminine singular agreement.

So:

• الذكريات = memories
• حلوة = nice/lovely/beautiful, in the feminine singular form

This is very normal Arabic grammar, not a special exception for this one sentence.

In the present tense, Arabic normally does not use a word for am / is / are.

So:

• الذكريات دي حلوة literally looks like these memories beautiful
• but it means These memories are beautiful / nice / lovely

This is standard in both Egyptian Arabic and Standard Arabic.

Originally, حلو does relate to the idea of sweet, but in Egyptian Arabic it is used much more broadly.

حلوة can mean:

• sweet
• nice
• pretty
• beautiful
• lovely
• pleasant

So in a sentence about memories, حلوة usually means something like:

• beautiful
• lovely
• nice

not literally sugary-sweet.

The singular is ذكرى.

So:

• ذكرى = a memory / a recollection
• ذكريات = memories

This plural is formed with -ات, which is a very common plural ending, especially with many feminine nouns and borrowed patterns.

Because the sentence is built like this:

• الذكريات دي = the subject, these memories
• حلوة = the predicate, beautiful/nice

So the structure is:

• [subject] + [description]

That gives:

• الذكريات دي حلوة = These memories are lovely

Also, in Arabic, adjectives normally come after the noun anyway. So seeing descriptive words after nouns is very normal.

In Standard Arabic, you would more likely see something like:

• هذه الذكريات جميلة

Main differences:

• Egyptian Arabic uses دي after the noun.
• Standard Arabic often uses هذه before the noun.
• Egyptian Arabic uses حلوة very naturally in everyday speech.
• Standard Arabic would more often use جميلة in a formal context.

So الذكريات دي حلوة sounds natural and conversational in Egyptian Arabic.

This is a very useful distinction.

• الذكريات دي حلوة = These memories are lovely
• الذكريات الحلوة = the lovely memories

In the first sentence, حلوة is the predicate: it tells you something about the memories.

In the second phrase, الحلوة is an adjective inside the noun phrase: it identifies which memories you mean.

So:

• الذكريات دي حلوة = a full sentence
• الذكريات الحلوة = just a noun phrase, not a complete sentence by itself