אם אין מושב ליד החלון, אני רוצה מושב ליד המעבר.

אם means if.

It introduces a condition:

• אם אין מושב ליד החלון = If there isn’t a seat by the window

In other contexts, אם can also mean whether, but in this sentence it clearly means if.

אין is the standard Hebrew word for there is no / there isn’t / there are no.

Hebrew often expresses existence with:

• יש = there is / there are
• אין = there isn’t / there aren’t

So:

• אין מושב ליד החלון = There is no seat by the window

Hebrew does not use a present-tense verb like English is in this kind of sentence.

Hebrew does not have an indefinite article like English a or an.

So:

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

That means:

• אני רוצה מושב ליד המעבר literally looks like I want seat by the aisle
• but natural English is I want a seat by the aisle

The prefix ה־ means the.

So:

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

In English we often say window seat or aisle seat, but Hebrew commonly expresses this as:

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

So the definite article sounds natural here.

ליד means next to, by, beside, or sometimes near.

In this sentence:

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

For seats on a plane, bus, or train, by or next to is a very natural translation.

Because each location phrase needs its own preposition.

The sentence has two separate seat descriptions:

• מושב ליד החלון
• מושב ליד המעבר

Hebrew does not normally skip the second ליד here. Repeating it is the natural way to say it.

Sometimes Hebrew can leave out the subject pronoun, but here אני is very natural and helpful.

The form רוצה tells you gender and number, but not person very clearly by itself in the way English verbs do. So אני רוצה is the normal, clear way to say I want.

Without אני, the sentence could sound less complete unless the context already makes the subject obvious.

Yes, but only in pronunciation, not in the usual unpointed spelling.

The spelling רוצה can be read as:

• rotze for a male speaker
• rotza for a female speaker

So:

• אני רוצה can mean I want said by either a man or a woman
• the written form stays the same
• the pronunciation changes

מושב means seat, especially in transportation or assigned seating.

כיסא means chair and is more general.

So on a plane, train, or bus, מושב is the more natural word if you are asking for a particular place to sit.

מעבר literally means something like passage, way through, or aisle, depending on context.

In a travel context, ליד המעבר means by the aisle.

So even if the core meaning of מעבר is broader than English aisle, this is exactly the right word in this kind of sentence.

The given word order is very natural:

• אם אין מושב ליד החלון, אני רוצה מושב ליד המעבר.

It starts with the condition and then gives the result or preference.

You could rearrange the sentence, but this version is the clearest and most standard for a request like this. Starting with the if clause is especially natural when you are giving a backup preference.

A simple pronunciation guide is:

Im ein moshav leyad ha-chalon, ani rotzeh / rotzah moshav leyad ha-ma’avar.

A few notes:

• אם = im
• אין = ein
• ליד = leyad
• החלון = ha-chalon
• המעבר = ha-ma’avar
• רוצה = rotzeh for a male speaker, rotzah for a female speaker

The stress is usually near the end of words like ha-chaLON and ma’aVAR.