النظام الداخلي جاهز تماما.

In Arabic, the present-tense verb to be is usually not written or spoken in simple statements like this.

So:

• النظام الداخلي جاهز تماما
• literally: the internal system ready completely
• natural English: The internal system is completely ready

If you wanted was, will be, etc., Arabic would use a verb such as كان.

This is a nominal sentence in Arabic.

It has:

• النظام الداخلي = the subject/topic (المبتدأ)
• جاهز تماما = the predicate/comment (الخبر)

So the structure is basically:

• [subject] + [description]

That is very common in Arabic.

It is noun + adjective, not iḍāfa.

• النظام = the system
• الداخلي = internal

A good clue is that both words have ال-. In an iḍāfa, the first noun normally would not take ال.

So here, الداخلي is simply describing النظام:

• النظام الداخلي = the internal system / the internal regulations, depending on context

Because Arabic adjectives agree with the nouns they describe.

Since النظام is definite (the system), the adjective must also be definite:

• النظام الداخلي
• not النظام داخلي

In Arabic, adjectives usually match the noun in:

• definiteness
• gender
• number
• case

So the double ال- here is exactly what you should expect.

The -ي here is part of a very common adjective pattern in Arabic called the nisba ending.

It often turns a noun or idea into an adjective, somewhat like English -al, -ic, or -ary.

So:

• داخل = inside / interior
• داخلي = internal / interior

This pattern appears everywhere in Arabic, for example:

• دولة → دولي = international
• رسم → رسمي = official
• شخص → شخصي = personal

Because it agrees with النظام, which is singular masculine.

So Arabic uses:

• جاهز for masculine singular
• جاهزة for feminine singular

For example:

• الخطة جاهزة = The plan is ready.
• النظام جاهز = The system is ready.

Here, النظام is masculine singular, so جاهز is the correct form.

تماما means something like:

• completely
• entirely
• totally

It is modifying جاهز, so:

• جاهز تماما = completely ready

Grammatically, تمامًا is being used adverbially, and that is why it appears in the accusative-style form with tanwīn fatḥ in full vocalization.

Yes. The sentence is still complete without it:

• النظام الداخلي جاهز = The internal system is ready.

Adding تماما just makes the statement stronger:

• النظام الداخلي جاهز تماما = The internal system is completely ready.

So تماما is optional emphasis, not a required part of the grammar.

A careful pronunciation is:

an-niẓāmu ad-dākhiliyyu jāhizun tamāman

A few key points:

• In النظام, the ل of ال is not pronounced clearly because ن is a sun letter. So it sounds like an-niẓām, not al-niẓām.
• In الداخلي, the same thing happens because د is also a sun letter. So it sounds like ad-dākhilī, not al-dākhilī.
• ظ in النظام is an emphatic sound, roughly like a heavy z.
• خ in داخلي is like the ch in Scottish loch or German Bach.

With full case endings, it is:

النِّظَامُ الدَّاخِلِيُّ جَاهِزٌ تَمَامًا

Here is why:

• النِّظَامُ = nominative, because it is the subject
• الدَّاخِلِيُّ = nominative too, because it is an adjective describing النظام
• جَاهِزٌ = nominative, because it is the predicate
• تَمَامًا = accusative adverbial form

In normal Arabic writing, these short vowels are usually omitted, which is why you see:

النظام الداخلي جاهز تماما