תשמרי בשבילי מקום ליד החלון.

Because תשמרי is the 2nd person feminine singular form.

So this sentence is addressed to one female.

Related forms:

• to one male: תשמור בשבילי מקום ליד החלון
• to more than one person: תשמרו בשבילי מקום ליד החלון

In very traditional grammar, the imperative forms would be:

• feminine singular: שמרי
• masculine singular: שמור
• plural: שמרו

But in everyday Modern Hebrew, speakers often use the future form like תשמרי when giving a request or command.

Formally, תשמרי is a future-tense form: you will keep / you will save addressed to a woman.

But in spoken Modern Hebrew, future forms are very often used as commands or requests. So here it means something like keep / save / reserve.

That means:

• תשמרי can mean you will keep in one context
• and keep! or please keep! in another context

The sentence context makes it clear that this is a request.

The root is ש-מ-ר, which carries the basic idea of keeping, guarding, watching, preserving.

From that root you get forms like:

• לשמור = to keep / to guard
• שומר = guarding / keeping, or a guard depending on context
• שמרי = keep! (to a woman, standard imperative)
• תשמרי = you will keep / keep! (to a woman)

In this sentence, the idea is not literal guarding. It means save/reserve a spot.

Hebrew often uses לשמור מקום literally to keep a place for the idea of saving or reserving a seat/spot.

So מקום literally means place, but in this kind of sentence it often means:

• a seat
• a spot
• room for someone

This is very natural Hebrew. English might prefer save me a seat, but Hebrew uses keep a place for me.

בשבילי means for me.

It is built from:

• בשביל = for
• -י = me

So:

• בשבילי = for me
• בשבילך = for you
• בשבילו = for him
• בשבילה = for her

In this sentence, בשבילי means the place is being kept for my benefit.

Yes, absolutely. שמרי לי מקום or תשמרי לי מקום is very common.

Compare the nuance:

• שמרי לי מקום = save me a seat / keep me a place
• תשמרי בשבילי מקום = keep a place for me

Both are natural.
לי is often shorter and very common in everyday speech.
בשבילי can sound a bit more explicit or emphatic: for me.

Because ה- is the Hebrew definite article, meaning the.

So:

• החלון = the window
• מקום = a place / a spot

The sentence therefore means a place next to the window, not the place next to the window.

If you wanted to say the place next to the window, you would say:

• המקום ליד החלון

ליד means next to, beside, or by.

So:

• ליד החלון = next to the window / by the window

It is a very common preposition in Hebrew.

Examples:

• ליד הדלת = by the door
• ליד הבית = next to the house
• שב לידי = sit next to me

The word order here is very natural:

תשמרי | בשבילי | מקום | ליד החלון
verb | for me | place | next to the window

This is basically:

• request/action first
• beneficiary next
• object after that
• location/detail last

Hebrew word order is somewhat flexible, but this version sounds normal and straightforward.

For example, you could also hear:

• תשמרי מקום בשבילי ליד החלון

That is also understandable, but the original order is perfectly natural.

A simple pronunciation guide is:

tishmeri bishvili makom leyad hachalon

Rough stress:

• tishmeRI
• bishviLI
• maKOM
• leYAD
• hachaLON

A few notes:

• ח in החלון is a throaty sound that English does not really have
• תשמרי is pronounced tishmeri, not tashmeri

By itself, it sounds like a normal everyday request. Hebrew often sounds more direct than English without being rude.

If you want to make it more polite, you could add:

• בבקשה = please
• נא = please, more formal/literary

Examples:

• תשמרי בשבילי מקום ליד החלון, בבקשה
• שמרי לי מקום ליד החלון, בבקשה

So the original sentence is fine, especially between friends or in casual conversation.

Yes, the verb לשמור can mean several related things:

• to guard
• to keep
• to preserve
• to save
• to reserve

The exact meaning depends on context.

For example:

• תשמרי על התיק = watch the bag / keep an eye on the bag
• תשמרי את הקבלה = keep the receipt
• תשמרי לי מקום = save me a seat

So in this sentence, because the object is מקום, the meaning is clearly save/reserve a place, not guard in the security sense.