אני מעדיפה מושב ליד החלון, אבל אחותי רוצה מושב ליד המעבר.

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

• אני מעדיפה = I prefer (said by a woman)
• אני מעדיף = I prefer (said by a man)

So the word אני itself does not show gender, but the verb does.

No. אני always means I, for both men and women.

What changes is the verb in the present tense:

• אני מעדיף = a man says I prefer
• אני מעדיפה = a woman says I prefer

The same idea applies elsewhere in the sentence with רוצה, although that one is a little less obvious in normal spelling.

Good question. In standard unpointed Hebrew spelling, the masculine singular and feminine singular forms of some present-tense verbs can look the same.

With vowels marked, they are different:

• masculine: רוֹצֶה = rotze
• feminine: רוֹצָה = rotza

But without vowel marks, both are usually written רוצה.

Since אחותי means my sister, you understand that this should be read as the feminine form: rotza.

The -י at the end is a possessive suffix meaning my.

So:

• אחות = sister
• אחותי = my sister

This is very common in Hebrew:

• ספר = book
• ספרי = my book

So Hebrew often attaches possession directly to the noun instead of using a separate word like my.

Because Hebrew has no indefinite article. English has a / an, but Hebrew simply uses the noun by itself.

So:

• מושב can mean a seat or just seat, depending on context.

That is why מושב ליד החלון naturally means a seat by the window.

That ה is the Hebrew definite article, meaning the.

• חלון = window
• החלון = the window
• מעבר = passage / aisle
• המעבר = the aisle

So:

• ליד החלון = by the window
• ליד המעבר = by the aisle

Because את is only used before a definite direct object.

Here, מושב is indefinite: a seat, not the seat. So you do not use את.

Compare:

• אני רוצה מושב = I want a seat
• אני רוצה את המושב = I want the seat

That is an important Hebrew pattern.

ליד usually means next to, by, beside, or near, depending on context.

In this sentence:

• מושב ליד החלון = a seat by the window
• מושב ליד המעבר = a seat by the aisle

In travel contexts, this is the normal way to express window seat and aisle seat.

Because Hebrew often expresses this idea with a noun plus a prepositional phrase:

• מושב ליד החלון = literally a seat next to the window
• מושב ליד המעבר = literally a seat next to the aisle

This is very natural Hebrew. English often compresses such ideas into compounds like window seat or aisle seat, but Hebrew commonly spells the relationship out more directly.

אבל means but.

It connects the two contrasting parts:

• אני מעדיפה מושב ליד החלון
• אבל אחותי רוצה מושב ליד המעבר

So the sentence sets up a contrast between the speaker’s preference and the sister’s preference.

The sentence follows a very common Hebrew pattern:

subject + verb + object / complement

So:

• אני מעדיפה מושב ליד החלון = I prefer a seat by the window
• אחותי רוצה מושב ליד המעבר = my sister wants a seat by the aisle

Hebrew word order can sometimes be flexible for emphasis, but this sentence uses a very standard and natural order.

A simple transliteration is:

Ani ma'adifa moshav leyad ha-chalon, aval achoti rotza moshav leyad ha-ma'avar.

A more natural English-style guide might be:

ah-NEE mah-ah-DEE-fah moh-SHAV leh-YAD hah-kha-LON, ah-VAL a-kho-TEE ro-TSA moh-SHAV leh-YAD hah-ma-ah-VAR

A few notes:

• ch in chalon is the throaty sound heard in words like Bach or Chanukah
• rotza is the feminine pronunciation here because אחותי is feminine
• ma'avar has a slight break between the two vowel sounds because of the ע