לפני המסיבה אני מתלבשת לאט, כי אני לא יודעת אם ללבוש שמלה או חולצה.

Because the speaker is female. In Hebrew present tense, verbs agree with the subject in gender and number.

• אני מתלבשת = I get dressed / I am getting dressed, said by a woman
• אני יודעת = I know, said by a woman

If a man were speaking, it would be:

• אני מתלבש
• אני לא יודע

So a masculine version of the sentence would be:

לפני המסיבה אני מתלבש לאט, כי אני לא יודע אם ללבוש שמלה או חולצה.

מתלבשת comes from the verb להתלבש, which means to get dressed or to dress oneself.

This is slightly different from simply to wear. It focuses on the act of putting clothes on or getting ready.

So in this sentence, אני מתלבשת לאט means that the speaker gets dressed slowly.

These are related, but they are not the same form or exactly the same idea.

• מתלבשת = present tense of להתלבש = getting dressed
• ללבוש = infinitive of ללבוש = to wear / to put on

So the sentence is making a useful distinction:

• First: I get dressed slowly
• Then: I don’t know whether to wear a dress or a shirt

In other words, the speaker is in the process of getting dressed, but is unsure which item to put on.

Both words come from the Hebrew root ל-ב-ש, which is connected to clothing and wearing clothes.

You will often see this root in words such as:

• ללבוש = to wear / to put on
• להתלבש = to get dressed
• מלבוש = garment, clothing item

Recognizing roots is very helpful in Hebrew, because it lets you connect words that belong to the same idea.

Hebrew often includes subject pronouns in the present tense, because present-tense verb forms usually show gender and number, but not clearly person.

For example, יודעת means knowing in the feminine singular, but by itself it does not automatically mean only I know. It could also refer to she knows, depending on context.

That is why אני is often kept:

• אני מתלבשת
• אני לא יודעת

In casual speech, speakers sometimes drop אני if the meaning is clear from context, but including it is very normal and often clearer.

Here אם means whether, not a condition.

After verbs like know, ask, check, or see, Hebrew often uses אם the same way English uses whether:

• אני לא יודעת אם... = I don’t know whether...

So in this sentence, אם introduces an indirect question: whether to wear a dress or a shirt.

This is different from a conditional sentence like:

• אם ירד גשם, לא נצא = If it rains, we won’t go out

Same word, different function.

Because the structure here is לא יודעת אם + infinitive, which is a common Hebrew pattern for saying not know whether to do something.

So:

• אני לא יודעת אם ללבוש שמלה או חולצה = I don’t know whether to wear a dress or a shirt

This is very natural Hebrew.

Hebrew often uses the infinitive after words like יודע/ת, especially when talking about uncertainty about an action.

Because המסיבה is a specific party, while שמלה and חולצה are indefinite items.

• המסיבה = the party
• שמלה = a dress
• חולצה = a shirt / blouse

Hebrew uses ה־ for definiteness, but there is no separate word for a/an. So an indefinite noun usually appears with no article at all.

If the speaker meant specific items, Hebrew could say:

• השמלה או החולצה = the dress or the shirt

But here the idea is more general: she has not decided what to wear.

Hebrew often puts a time expression at the beginning of the sentence to set the scene.

So לפני המסיבה means before the party, and placing it first gives the listener the time context right away.

This is very natural word order in Hebrew.

You could also say:

• אני מתלבשת לאט לפני המסיבה...

But starting with לפני המסיבה sounds smooth and common.

לפני means before.

It is usually followed by a noun or noun phrase:

• לפני המסיבה = before the party
• לפני השיעור = before the lesson
• לפני ארוחת הערב = before dinner

It can also appear before a verb phrase in other structures, but in this sentence it is simply a preposition followed by a noun.

לאט means slowly, and it functions as an adverb.

In Hebrew, adverbs often come after the verb, so:

• אני מתלבשת לאט = I get dressed slowly

That is the most neutral and natural order here.

Hebrew word order can sometimes change for emphasis, but this placement is the standard one.

חולצה is a general word for an upper-body garment such as a shirt or blouse, depending on context.

So in a sentence like this, it can be understood broadly as a top. The exact English choice may depend on the situation, style, and who is speaking.

That kind of overlap is very common when moving between Hebrew and English vocabulary.

Hebrew changes the verb forms to match gender and number.

For a male speaker:

• לפני המסיבה אני מתלבש לאט, כי אני לא יודע אם ללבוש שמלה או חולצה.

For a group of women:

• לפני המסיבה אנחנו מתלבשות לאט, כי אנחנו לא יודעות אם ללבוש שמלה או חולצה.

For a group of men or a mixed group:

• לפני המסיבה אנחנו מתלבשים לאט, כי אנחנו לא יודעים אם ללבוש שמלה או חולצה.

This is one of the most important features of Hebrew grammar: present-tense forms change for gender and number.