أولا، تحقق من الرقم.

أولا means first, firstly, or to begin with.

It is commonly used to introduce the first step in a set of instructions. So in this sentence, it signals that the speaker is giving directions in order:

• أولا = first
• تحقق من الرقم = check the number

Putting أولا at the beginning is very natural in Arabic, just as First, ... is natural in English.

The fully vocalized form is أولًا.

That final mark is tanwīn fatḥ and shows that the word is being used adverbially, something like firstly or first of all. In normal everyday Arabic writing, short vowels and tanwīn are often omitted, so you will usually just see:

• أولا

Both refer to the same word here.

Here it is a command: check or verify.

Without vowel marks, تحقق can look ambiguous to a learner, because Arabic often leaves short vowels unwritten. In this sentence, the meaning and context make it clear that it is the imperative form:

• تَحَقَّقْ = check! / make sure!

So the sentence is giving an instruction, not describing something that already happened.

The verb is تَحَقَّقَ.

In this sentence, the form used is the imperative addressed to one male or to someone in a general instructional sense:

• تَحَقَّقْ = check / verify

A useful way to think of it is that the verb often means to make sure, to verify, or to ascertain.

Because تَحَقَّقَ مِنْ is a common pattern meaning to make sure of or to verify something.

So:

• تحقق من الرقم = verify the number / make sure of the number

This is very natural Arabic. The preposition من is part of how this verb is commonly used in this meaning.

A very literal breakdown would be:

• تحقق = make sure
• من الرقم = of the number

But in smooth English, verify the number or check the number is the best translation.

الرقم means the number, while رقم means a number.

Using ال makes the noun definite. In context, this usually means a specific number is already known from the situation, such as:

• a phone number
• an account number
• a reference number
• a code

So تحقق من الرقم most naturally means check the number rather than check a number.

After the preposition من, the noun is in the genitive case.

So the fully vocalized form would be:

• مِنَ الرَّقْمِ

The final -i sound of the genitive is usually not written in ordinary Arabic text, which is why you normally just see:

• من الرقم

So even though the ending is not visible, grammatically it is genitive.

This form is the singular masculine imperative, but in many instructions it is also used in a general way, similar to English directions like Click here or Check the number.

More specifically:

• تَحَقَّقْ = command to one male
• In instructions, it can also function as a general default form

If you wanted other forms, they would change:

• to one woman: تَحَقَّقِي
• to two people: تَحَقَّقَا
• to a group of men or mixed group: تَحَقَّقُوا
• to a group of women: تَحَقَّقْنَ

A careful pronunciation would be:

• أوَّلًا، تَحَقَّقْ مِنَ الرَّقْمِ

A simple transliteration is:

• awjalan, taḥaqqaq min ar-raqm

Notes:

• أولا is pronounced roughly aw-wa-lan
• تحقق has a doubled q sound in careful pronunciation because of the underlying shadda
• الرقم is ar-raqm, because the ل of ال assimilates to ر

Because ر is a sun letter.

When ال comes before a sun letter, the l sound is not pronounced separately; instead, the following consonant is doubled in pronunciation.

So:

• written: الرقم
• pronounced: ar-raqm

This is a pronunciation rule only. The spelling stays the same.

Yes. Arabic has several verbs that can fit similar contexts, but they are not always identical in tone.

For example:

• تحقق من الرقم = verify the number / make sure of the number
• افحص الرقم = inspect the number / check the number
• راجع الرقم = review the number
• تأكد من الرقم = make sure of the number

In many practical contexts, تحقق من and تأكد من are especially common for verifying information.