فتحة التصريف صغيرة.

A fully vocalized version is:

فَتْحَةُ التَّصْرِيفِ صَغِيرَةٌ

A careful pronunciation is roughly:

fatḥatu t-taṣrīfi ṣaghīratun

A few things to notice:

• فَتْحَةُ = fatḥatu
• التَّصْرِيفِ = at-taṣrīfi in isolation, but after فتحةُ you will hear t-taṣrīfi
• صَغِيرَةٌ = ṣaghīratun

In normal unvocalized Arabic writing, those short vowels are usually not written, so you may just see:

فتحة التصريف صغيرة

Because Arabic often leaves out is / am / are in the present tense.

So a sentence like:

• فتحة التصريف صغيرة

literally looks like:

• The ... fatḥa small

but naturally means:

• The ... fatḥa is small

This is called a nominal sentence in Arabic. In the present tense, Arabic normally does not use a separate verb for is.

If you wanted a past-tense version, then Arabic would use a verb, for example:

• كانت فتحة التصريف صغيرة = The ... fatḥa was small

The sentence has two main parts:

1. فتحةُ التصريفِ — the subject/topic part
2. صغيرةٌ — the predicate/comment part

So the structure is:

• [subject phrase] + [predicate adjective]

More specifically:

• فتحةُ = the head noun
• التصريفِ = attached to it in an iḍāfa structure
• صغيرةٌ = the predicate describing the subject phrase

So the whole sentence is a standard Arabic nominal sentence:
فتحةُ التصريفِ صغيرةٌ = The ... fatḥa is small.

Because it is the subject of the nominal sentence, so it is in the nominative case.

That is why the fully vocalized form is:

• فَتْحَةُ

not:

• فَتْحَةَ
• فَتْحَةِ

In Arabic grammar, the subject of a nominal sentence is normally nominative.

Also, because فتحة is the first noun in an iḍāfa construction, it takes its case ending but does not take tanwīn.

So:

• فتحةُ التصريفِ = nominative فتحةُ
  • genitive التصريفِ

Because it is the second part of an iḍāfa construction, and the second noun in an iḍāfa is put in the genitive case.

So:

• فتحةُ التصريفِ

means something like the fatḥa/opening of al-taṣrīf

In an iḍāfa:

• the first noun is called muḍāf
• the second noun is called muḍāf ilayh

The muḍāf ilayh is genitive, so:

• التصريفِ ends in -i

Because in an iḍāfa construction, the first noun usually does not take الـ.

So Arabic says:

• فتحةُ التصريفِ

not:

• الفتحةُ التصريفِ

The definiteness of the whole phrase is determined by the second noun.

Since التصريف has الـ, the whole phrase فتحة التصريف is definite.

This is a very important pattern in Arabic:

• بابُ البيتِ = the door of the house
• كتابُ الطالبِ = the student’s book
• فتحةُ التصريفِ = the ... of al-taṣrīf

So even without الـ on فتحة, the whole phrase can still be definite.

Because فتحة is in an iḍāfa construction, and the first noun in iḍāfa does not take tanwīn.

So we get:

• فَتْحَةُ التَّصْرِيفِ

not:

• فَتْحَةٌ التَّصْرِيفِ

But صغيرةٌ is the predicate, and it is an ordinary indefinite adjective/predicate here, so it can take tanwīn:

• صغيرةٌ

This is a very common contrast:

• كتابُ الطالبِ جديدٌ
• The student’s book is new

Here too:

• كتابُ has no tanwīn because it is muḍāf
• جديدٌ has tanwīn because it is the predicate

Because it agrees with فتحة, which is a feminine singular noun.

In Arabic, adjectives and predicate adjectives usually agree with the noun they describe in:

• gender
• number
• definiteness sometimes, depending on the construction

Since فتحة is feminine singular, the predicate is also feminine singular:

• صغيرةٌ = feminine singular
• not صغيرٌ = masculine singular

So Arabic uses:

• فتحةُ التصريفِ صغيرةٌ

just as it would say:

• السيارةُ صغيرةٌ = The car is small

Here it is the predicate of the whole sentence, not just an adjective inside the noun phrase.

That matters because Arabic has two similar-looking patterns:

1. Noun + adjective inside one phrase

   • فتحةٌ صغيرةٌ = a small fatḥa

2. Subject + predicate as a full sentence

   • فتحةُ التصريفِ صغيرةٌ = The ... fatḥa is small

In your sentence, فتحةُ التصريفِ is a complete subject phrase, and صغيرةٌ tells us something about it.

A clue is the meaning: it forms a complete statement, not just a noun phrase.

Because ة (tāʾ marbūṭa) is often pronounced as -a / -ah in pause, but as -t when the word is grammatically connected to what follows.

So:

• in pause: فتحة ≈ fatḥah
• in connected speech with case ending: فَتْحَةُ = fatḥatu

And because it is followed by another word in an iḍāfa phrase, the t sound is heard clearly:

• فَتْحَةُ التَّصْرِيفِ
• fatḥatu t-taṣrīfi

This is very normal with tāʾ marbūṭa.

Because ت is a sun letter.

When الـ comes before a sun letter, the l sound of al- is not pronounced. Instead, the following consonant is doubled.

So:

• التصريف is pronounced:
• at-taṣrīf

not:

• al-taṣrīf

In your full sentence, after فتحةُ, this comes out as:

• fatḥatu t-taṣrīfi

The written shadda on ت shows that doubling:

• التَّصريف

This is the same pattern as in words like:

• الشمس → ash-shams
• الطالب → aṭ-ṭālib
• التمر → at-tamr

Because in a nominal sentence, the predicate is often indefinite, even when the subject is definite.

So Arabic commonly says:

• البيتُ كبيرٌ = The house is big
• السيارةُ سريعةٌ = The car is fast
• فتحةُ التصريفِ صغيرةٌ = The ... fatḥa is small

Here:

• فتحةُ التصريفِ is definite as a whole
• صغيرةٌ is the predicate, so it is naturally indefinite in form

This is normal Arabic sentence structure, not a mismatch.