القول في الكتاب.

It can be understood as a complete nominal sentence in Arabic.

A common basic analysis is:

• القولُ = the subject/topic (mubtadaʾ)
• في الكتابِ = the predicate/comment (khabar) in the form of a prepositional phrase

Arabic often allows this kind of sentence without a verb in the present tense.
That said, because Arabic is usually written without short vowels, a standalone phrase like this can sometimes be somewhat ambiguous out of context. But for a learner, treating it as a simple nominal sentence is the most natural reading.

Because in Modern Standard Arabic, the verb to be is normally not stated in the present tense.

So where English says:

• The statement is in the book

Arabic can simply say:

• القولُ في الكتابِ

The idea of is is understood automatically.

If you wanted the past tense, Arabic would usually use كان:

• كان القولُ في الكتابِ = The statement was in the book

في is a preposition. It very often means in, inside, and sometimes in/on/about, depending on context.

Here it introduces the noun الكتاب and forms the prepositional phrase:

• في الكتابِ = in the book

So grammatically, في is the word that links the noun to the rest of the sentence.

Because nouns after prepositions are genitive in Arabic.

Since في is a preposition, the noun after it must be in the majrūr form:

• في الكتابِ

If the short vowels are written, you would see a kasra at the end: الكتابِ.

So the rule is very simple:

• في
  • noun → that noun becomes genitive

Because الـ is the Arabic definite article, equivalent to the.

So:

• القول = the statement / the saying
• الكتاب = the book

Arabic marks definiteness directly on each noun, unless a different structure is being used.

This sentence is not an iḍāfa construction, because the two nouns are not directly attached to each other. They are separated by the preposition في.

As a simple standalone nominal sentence, it would normally be read as:

• القَوْلُ في الكِتابِ
• al-qawlu fī al-kitābi

Here is what is happening:

• القَوْلُ ends in -u because it is nominative
• الكِتابِ ends in -i because it comes after في

In ordinary Arabic writing, these short vowels are usually omitted, so learners have to infer them from grammar and context.

If this is being read as a nominal sentence, القولُ is the subject/topic of the sentence, so it is in the nominative case.

That is why the full form is:

• القَوْلُ

This is the normal pattern for the first main noun in a basic nominal sentence:

• subject/topic = nominative
• noun after a preposition = genitive

So the contrast here is:

• القَوْلُ → nominative
• الكِتابِ → genitive

Yes. In both words, the l of الـ is pronounced.

That is because:

• ق in القول is a moon letter
• ك in الكتاب is also a moon letter

With moon letters, the l sound stays:

• al-qawl
• al-kitāb

If the next letter were a sun letter, the l would assimilate instead.

A careful pronunciation is:

• al-qawl or, with full case ending, al-qawlu

A few points:

• ق (qāf) is deeper and farther back than English k
• aw sounds like the vowel glide in cow
• ل is a normal l
• The whole word is one syllable after the article: qawl

So:

• القولُ في الكتابِ
• al-qawlu fī al-kitābi

Because the usual basic pattern here is:

• subject/topic first
• then the predicate/comment

So:

• القولُ = what the sentence is about
• في الكتابِ = what is being said about it

Arabic can also move parts of a sentence for emphasis, but the order here is very normal and straightforward for learners.

Not necessarily. Depending on context, القول can be translated in different ways, such as:

• statement
• saying
• speech
• utterance
• opinion or view in some contexts

So even if the grammar stays the same, the best English word may change depending on the wider text. This is very common in Arabic vocabulary.