כשאני כותבת מסמך רשמי, אני מזדקקת לעזרה רק אם יש מילה שאני לא מכירה.

Because the speaker is female.

In Hebrew present tense, verbs look like adjective-like forms and agree with the subject in gender and number.

So:

• אני כותבת = I write / I am writing, said by a woman
• אני מזדקקת = I need / I require, said by a woman
• אני לא מכירה = I don’t know / I’m not familiar with, said by a woman

A male speaker would say:

• כשאני כותב מסמך רשמי, אני מזדקק לעזרה רק אם יש מילה שאני לא מכיר.

כשאני means when I.

It is made of:

• כש־ = when
• אני = I

So:

• כשאני כותבת = when I write / when I’m writing

The כש־ part is a very common shortened form of כאשר.
So כשאני is less formal and very natural, while כאשר אני sounds more formal or literary.

Hebrew present tense uses forms like כותבת, which originally come from participles, but in modern Hebrew they function as the normal present tense.

So אני כותבת can mean:

• I write
• I am writing

The exact meaning depends on context.

Here, with כשאני, the sense is general or habitual:

• כשאני כותבת מסמך רשמי = When I write an official document

not necessarily only while I am in the middle of writing one.

Because in Hebrew, adjectives usually come after the noun.

So:

• מסמך = document
• רשמי = official

Together:

• מסמך רשמי = an official document

Also, the adjective must agree with the noun in gender, number, and definiteness.

Here:

• מסמך is masculine singular
• so רשמי is also masculine singular

If the noun were definite, both words would be definite:

• המסמך הרשמי = the official document

מזדקקת לעזרה means need help, but it sounds a bit more formal or elevated than צריכה עזרה.

The verb is:

• להזדקק ל־ = to need, to require, to be in need of

So:

• אני מזדקקת לעזרה = I need help / I require help

A more everyday version would be:

• אני צריכה עזרה = I need help

Both are correct, but מזדקקת fits the somewhat formal tone of a sentence about writing an official document.

Because the verb להזדקק requires the preposition ל־, meaning to.

So the pattern is:

• להזדקק ל...
• מזדקק/ת ל...

Examples:

• אני מזדקקת לעזרה = I need help
• הוא מזדקק לזמן = he needs time
• הם מזדקקים להסבר = they need an explanation

This is just something you learn together with the verb, like learning that some English verbs need a specific preposition.

רק אם means only if.

• רק = only
• אם = if

Then יש means there is / there are.

So:

• רק אם יש מילה = only if there is a word

This introduces the condition under which the speaker needs help.

Hebrew uses יש to express existence: there is / there are.

So:

• יש מילה = there is a word

In this sentence:

• רק אם יש מילה שאני לא מכירה = only if there is a word that I don’t know

Notice that יש does not change for gender or number the way ordinary verbs do. It is a fixed existential word.

It is a relative clause: that I don’t know.

So:

• מילה = a word
• שאני לא מכירה = that I don’t know

Together:

• מילה שאני לא מכירה = a word that I don’t know

Here ש־ is functioning like that / which in English.

This is a very common Hebrew structure:

• ספר שאני קוראת = a book that I’m reading
• איש שאני מכירה = a man that I know
• מקום שאנחנו אוהבים = a place that we like

Because with מילה meaning word, Hebrew often uses להכיר in the sense of to be familiar with / to know.

So:

• אני לא מכירה את המילה הזאת = I don’t know this word / I’m not familiar with this word

Using יודעת here would sound less natural unless you are talking about knowing some fact or information about the word.

Also, מכירה agrees with אני, not with מילה.

That is important:

• the subject is אני
• the object is מילה

So מכירה is feminine because the speaker is female, not because מילה is feminine.

Because in a relative clause like this, the object is understood from the noun that comes before it.

So:

• מילה שאני לא מכירה = a word that I don’t know

Hebrew normally does not need to repeat the object with אותה here in standard usage.

Adding it would usually sound unnecessary or less standard in this kind of sentence.

This works much like English:

• a word that I don’t know

You do not say:

• a word that I don’t know it

Hebrew behaves similarly here.

Yes, somewhat.

The main reasons are:

• מסמך רשמי = official document
• מזדקקת לעזרה = a relatively formal way to say need help

A more everyday version might be:

• כשאני כותבת מסמך רשמי, אני צריכה עזרה רק אם יש מילה שאני לא מכירה.

That version means basically the same thing, but sounds a little more conversational.