التليفون ده شاشته فيها مشكلة.

A common Egyptian-style pronunciation would be:

it-tilifōn da shāshto fīha moshkila

A few notes:

• التليفون is not usually pronounced al-tilifon in connected speech.
• Because ت is a sun letter, the ل of الـ is absorbed, so you hear something like it-tilifōn or et-telefōn.
• فيها is fī-ha = in it / it has depending on context.

In Egyptian Arabic, demonstratives like ده often come after the noun.

So:

• التليفون ده = this phone
• البنت دي = this girl
• البيت ده = this house

This is one of the first word-order differences English speakers notice.

شاشته means its screen.

It breaks down like this:

• شاشة = screen
• ـه = his / its

So:

• شاشته = his screen or its screen

Here it means its screen, because it refers to the phone.

Because the final ة in a feminine noun often turns into a t sound when another ending is attached.

So:

• شاشة on its own
• شاشته when you add ـه

This is very common in Arabic. The same thing happens in many words ending in ة.

Because فيها refers to the screen, and screen (شاشة) is grammatically feminine.

So:

• فيه = in it for a masculine noun
• فيها = in it for a feminine noun

Even though the whole sentence is about the phone, the pronoun in فيها points back to شاشة, not التليفون.

In Arabic, the verb to be is usually omitted in the present tense.

So instead of saying something like its screen is with a problem, Egyptian Arabic naturally says:

• شاشته فيها مشكلة
• literally: its screen, in it a problem
• naturally: its screen has a problem / there’s a problem with its screen

This is normal Arabic grammar.

Literally, it means something like:

there is a problem in it

In natural English, we usually say:

• it has a problem
• there’s a problem with it
• there’s something wrong with it

So في here is still basically in, but the whole expression works like has a problem.

It may feel repetitive in English, but it is very natural in Egyptian Arabic.

The structure is:

• التليفون ده = the topic: this phone
• شاشته فيها مشكلة = the comment: its screen has a problem

So the sentence works like:

As for this phone, its screen has a problem.

This kind of topic-comment structure is very common in spoken Arabic.

Yes, that is also natural.

Compare:

• التليفون ده شاشته فيها مشكلة
  • more directly focuses on the screen
• التليفون ده فيه مشكلة في شاشته
  • starts with the idea that the phone has a problem, then specifies that it is in the screen

Both are good Egyptian Arabic.

Because it means a problem, not the problem.

In Arabic:

• مشكلة = a problem
• المشكلة = the problem

So the sentence is saying the screen has some problem, not referring to a previously known specific problem.

Yes.

The suffix ـه can mean:

• his
• its for a masculine noun

Since التليفون is grammatically masculine, Arabic uses ـه for its here.

So in context:

• شاشته = its screen, not his screen

It is clearly natural Egyptian Arabic, especially because of ده and the overall spoken structure.

Speakers of other Arabic dialects would probably understand it, but they might phrase it differently in their own dialects.

A more formal MSA-style version would be different, such as:

شاشة هذا الهاتف فيها مشكلة
or
هناك مشكلة في شاشة هذا الهاتف

But for everyday Egyptian speech, التليفون ده شاشته فيها مشكلة is very natural.