كتبت الرقم غلط في الاستمارة، فالموظفة قالت لي اكتب الرقم تاني.

Because Arabic usually does not need an explicit subject pronoun when the verb already shows who did the action.

• كتبت here means I wrote
• the ending -ت tells you it is first person singular in the past

So أنا is optional. You could say أنا كتبت for emphasis, but most of the time كتبت by itself is enough.

غلط means wrong, incorrect, or by mistake.

In this sentence, it works like an adverb in English:

• كتبت الرقم غلط = I wrote the number wrong
• more naturally in English: I wrote the number incorrectly

In Egyptian Arabic, غلط is very common and flexible. It can also be used as a noun or adjective in other contexts:

• ده غلط = This is wrong
• فيه غلط = There is a mistake

This is just a normal Arabic usage. في literally means in, but Arabic often uses it where English would say on, especially with documents, forms, and places where information is entered.

So:

• في الاستمارة literally = in the form
• natural English meaning = on the form

This is something you should get used to rather than translate word-for-word.

The فـ here means something like so, then, or therefore.

It connects the two parts:

• كتبت الرقم غلط في الاستمارة
• فالموظفة قالت لي...

So the sense is:

• I wrote the number wrong on the form, so the employee told me...

In Arabic, فـ is a very common connector and is often attached directly to the next word.

Because of the ending ـة.

• موظف = male employee
• موظفة = female employee

The verb also matches:

• قالت = she said
• قال = he said

So both الموظفة and قالت show that the employee is female.

Because قال normally takes the person being spoken to with لـ, meaning to.

So:

• قالت لي = she said to me
• قالت له = she said to him
• قالت لهم = she said to them

Using قالتني would not be the normal way to say this. With قال, Arabic usually uses لـ for the listener.

Because Arabic can report speech very directly, especially in everyday language.

Here the structure is basically:

• she said to me: write the number again

Even if there are no quotation marks, the meaning is still direct speech or near-direct reported speech.

So:

• قالت لي اكتب الرقم تاني
  means
• She told me, write the number again

In informal Arabic writing, punctuation is often lighter than in English.

Because اكتب here is the imperative form, meaning write!

In standard spelling, many imperative forms begin with a helping alif called hamzat al-wasl, which is written as ا.

So:

• اكتب = write!
• أكتب in formal spelling can mean I write

In real-life informal Arabic writing, people are not always fully consistent about writing hamza, but in this sentence اكتب is clearly the command write.

Yes. اكتب is a command to one male.

So this sentence implies that the employee was speaking to a male speaker.

Other forms would be:

• اكتب = write, said to one male
• اكتبي = write, said to one female
• اكتبوا = write, said to a group

So if the speaker were female and the wording were exact, you would expect قالت لي اكتبي الرقم تاني.

تاني is a very common Egyptian Arabic word meaning:

• again
• another time
• sometimes second depending on context

Here:

• اكتب الرقم تاني = write the number again

A longer version you may also hear is:

• مرة تانية = again, literally another time

تاني is colloquial Egyptian. In formal Arabic, you would more likely see مرة أخرى.

Yes, it could.

• اكتب الرقم تاني = write the number again
• اكتبه تاني = write it again

Both are natural. Repeating الرقم makes the sentence clearer and a little more explicit. Arabic often repeats nouns in places where English might prefer a pronoun.

So the version in your sentence is completely normal.

Yes. In informal Egyptian writing, both are common.

• قالت لي
• قالتلي

They mean the same thing. The second spelling reflects the way people actually say it in fast speech, with the preposition لـ attached to the verb.

You will often see this kind of spelling variation in dialect writing because colloquial Arabic spelling is less standardized than formal Arabic spelling.

One possible Cairo-style pronunciation is:

katabt ir-raʔm ghalat fil-istimara, فال-mowazzafa 'alet li ektib ir-raʔm tani

A more fully Arabic-script-based breakdown would be:

• كتبت → katabt
• الرقم → ir-raʔm
• غلط → ghalat
• في الاستمارة → fil-istimara
• فالموظفة → fal-mowazzafa
• قالت لي → 'alet li
• اكتب → ektib
• تاني → tani

A few notes:

• الرقم is often pronounced with a glottal stop in Egyptian, so raʔm
• اكتب is pronounced ektib in Egyptian
• تاني has a long aa sound: taani / tani

It is a mix of features that are very natural in everyday Egyptian Arabic.

Clearly colloquial Egyptian features include:

• غلط
• تاني
• the overall conversational style

But several words and forms are also shared with Standard Arabic or close to it:

• كتبت
• قالت
• الرقم
• الاستمارة
• الموظفة

This is very normal. Real spoken Egyptian often uses a mixture of:

• purely colloquial words
• words shared with Standard Arabic
• forms that are understood widely across Arabic varieties

So the sentence sounds natural and realistic for Egyptian everyday usage.