الصورة التي في الغرفة جميلة.

Because التي is the relative pronoun for a singular feminine definite noun.

Here, the noun being described is الصورة (the picture), which is:

• singular
• feminine
• definite because it has الـ

So Arabic uses التي to mean that / which in the picture that is in the room.

A quick comparison:

• الذي = singular masculine
• التي = singular feminine
• الذين = masculine plural
• اللاتي / اللواتي = feminine plural

Because صورة is a feminine noun in Arabic. One common sign of femininity is the ending ـة (taa marbuuTa), which appears here in صورة.

Since الصورة is feminine, words that refer back to it or describe it must also be feminine when agreement is required. That is why you get:

• التي and not الذي
• جميلة and not جميل

Because it refers to الصورة, which is feminine.

In this sentence, جميلة means beautiful, and it agrees with الصورة in gender. Since الصورة is feminine singular, the predicate is also feminine singular:

• الصورة جميلة
• the picture is beautiful

If the noun were masculine, you would use جميل instead.

In Arabic, the present tense of to be is usually not expressed in sentences like this.

So:

• الصورة جميلة literally looks like the picture beautiful
• but it means the picture is beautiful

This is called a nominal sentence in Arabic.

If you wanted a past or future meaning, Arabic would use a verb:

• كانت الصورة جميلة = the picture was beautiful
• ستكون الصورة جميلة = the picture will be beautiful

في الغرفة is a prepositional phrase meaning in the room.

It is part of the relative clause that describes الصورة:

• الصورة التي في الغرفة
• the picture that is in the room

So the structure is:

• الصورة = the picture
• التي في الغرفة = that is in the room
• جميلة = beautiful

Together: The picture that is in the room is beautiful.

Good question. Even though الصورة is definite, جميلة usually stays without الـ because it is the predicate of the sentence, not an attributive adjective directly attached to the noun.

Compare these two patterns:

• الصورة جميلة = The picture is beautiful
  • Here جميلة is the predicate.
• الصورة الجميلة = the beautiful picture
  • Here الجميلة is an adjective directly describing the noun inside one noun phrase.

So:

• with ال: adjective inside a noun phrase
• without ال: predicate in a sentence like X is beautiful

Yes. In Arabic, a relative clause can be built without an explicit verb when the meaning is something like that is in the room.

So التي في الغرفة literally looks like:

• which in the room

But it naturally means:

• which is in the room

Arabic often leaves out the present-tense is, just as it does in the main sentence.

Yes, Arabic can use different word orders, but this sentence is very normal and natural.

The basic structure here is:

• الصورة التي في الغرفة = topic / subject
• جميلة = predicate / comment about it

So the sentence starts with the thing being talked about, then says something about it:

• The picture that is in the room ... is beautiful.

That is a very common pattern in Arabic nominal sentences.

Because التي comes immediately after الصورة and introduces information that describes it.

The phrase is grouped like this:

• الصورة [التي في الغرفة] جميلة

So التي في الغرفة modifies الصورة.

Also, the meaning of the whole sentence supports that reading:

• the picture that is in the room is beautiful

If you wanted to describe الغرفة instead, the sentence would need a different structure.

In Modern Standard Arabic, التي is commonly pronounced allatī.

A rough breakdown:

• al-
• la
• tī

So: allatī

Also, the final ـي here is a long ee sound.

Because ص is a sun letter. When الـ comes before a sun letter, the l sound assimilates to the following consonant.

So:

• written: الصورة
• pronounced: aṣ-ṣūra

This happens in pronunciation, not spelling. The ل is still written, but it is not pronounced as l here.

Yes. In full formal vowelled Arabic, it would typically be:

الصُّورَةُ الَّتِي فِي الْغُرْفَةِ جَمِيلَةٌ

The main endings are:

• الصورةُ = nominative, because it is the subject/topic of the nominal sentence
• الغرفةِ = genitive, because it comes after the preposition في
• جميلةٌ = nominative predicate

In normal modern writing, these short case endings are usually omitted.

Not in standard Arabic, because الصورة is definite.

When a definite noun is followed by a relative clause, Arabic normally uses a relative pronoun such as:

• الذي
• التي
• and so on

So:

• الصورة التي في الغرفة جميلة is standard

Leaving out التي would not be correct in Modern Standard Arabic here.

They look similar, but they mean different things.

• الصورة الجميلة = the beautiful picture
  • This is just a noun phrase.
  • الجميلة is an adjective attached directly to الصورة.
• الصورة جميلة = the picture is beautiful
  • This is a full sentence.
  • جميلة is the predicate.

So the presence or absence of الـ on جميلة changes the structure and meaning.