Kolik knih si chceš půjčit v knihovně?

Because kolik normally takes the genitive plural in Czech.

• kniha = book
• knihy = books / of the book (depending on case)
• knih = of books (genitive plural)

So:

• Kolik knih = how many books

This is very common in Czech:

• kolik lidí = how many people
• kolik studentů = how many students
• kolik aut = how many cars

For English speakers, it helps to think of kolik as triggering a form similar to of books, even though English does not say it that way.

Si is a short form of the reflexive pronoun, and here it means something like for yourself.

So:

• půjčit can mean to lend or to borrow, depending on context
• půjčit si specifically means to borrow

That means:

• chceš si půjčit = you want to borrow
• without si, the meaning could become unclear or shift toward lend

This is a very important pattern in Czech:

• koupit si = to buy for oneself
• vzít si = to take for oneself
• půjčit si = to borrow

Because Czech does not use do-support like English does.

In English, you say:

• Do you want ...?

In Czech, the verb itself carries the meaning:

• chceš = you want

So the question is made mainly by:

• intonation in speech
• word order in writing and speech

Here:

• chceš = you want
• the sentence is a question because of the overall structure and the question mark

There is no need for a separate word like English do.

Because Czech often leaves out subject pronouns when they are already clear from the verb form.

• chceš already means you want (singular, informal)

So ty = you is unnecessary unless you want emphasis or contrast.

Compare:

• Chceš si půjčit knihu? = Do you want to borrow a book?
• Ty chceš si půjčit knihu? = You want to borrow a book? / Is it you who wants to borrow a book?

English usually requires the subject pronoun, but Czech often does not.

Knihovně is in the locative singular.

That is because it follows the preposition v when v means in or at a place.

• knihovna = library
• v knihovně = in the library / at the library

This is a standard pattern:

• v domě = in the house
• ve škole = in/at school
• v obchodě = in the shop

So in this sentence:

• v knihovně tells you the location where the borrowing happens

Because Czech is expressing the action as happening in/at the library, not emphasizing the source.

• v knihovně = in the library / at the library

In natural English, we often say borrow from the library, but Czech may prefer to frame it differently.

If you wanted to emphasize from the library, you might use a different structure, such as:

• z knihovny = from the library

But in this sentence, v knihovně is perfectly natural and means something like:

• How many books do you want to borrow at the library?

English and Czech do not always package location/source in exactly the same way.

Czech word order is more flexible than English word order, because grammatical roles are often shown by endings rather than position.

This sentence starts with Kolik knih because that is the question focus:

• Kolik knih = how many books

Then comes:

• si chceš půjčit = do you want to borrow

So the order feels very natural for asking about the number.

You may also hear other word orders in Czech, depending on emphasis, for example:

• Kolik si chceš půjčit knih v knihovně?

That is possible, but Kolik knih si chceš půjčit v knihovně? is a very normal and straightforward version.

For learners, the main thing is:

• Czech word order is flexible
• but not random
• word order often reflects emphasis and information structure

The dictionary form is chtít, which means to want.

Chceš is the 2nd person singular present tense form:

• chtít = to want
• chci = I want
• chceš = you want
• chce = he/she/it wants

The verb is a little irregular, so it is worth memorizing its forms.

The dictionary form is already půjčit.

It is the infinitive, meaning roughly to lend / to borrow, depending on the construction.

In this sentence, because of si, it means:

• půjčit si = to borrow

So:

• chceš si půjčit = you want to borrow

A useful contrast is:

• půjčit knihu kamarádovi = to lend a book to a friend
• půjčit si knihu = to borrow a book

This is about aspect, which is very important in Czech.

• půjčit = perfective
• půjčovat = imperfective

Here, půjčit si suggests borrowing as a single complete action:

• How many books do you want to borrow?

That is why půjčit sounds natural.

If you used půjčovat si, it would sound more like:

• borrowing repeatedly
• borrowing habitually
• focusing on the process rather than one completed action

English does not mark this contrast so strongly, so this can be tricky for learners.

Yes. Chceš is 2nd person singular informal, used with ty.

If you are speaking formally to one person, you would use chcete:

• Kolik knih si chcete půjčit v knihovně?

That can mean:

• How many books do you want to borrow in the library? (formal singular)
• or How many books do you want to borrow in the library? (plural you)

So Czech uses the same verb form for:

• formal singular
• plural

In Czech, ch is a single sound, not two separate sounds.

It is pronounced like the ch in Scottish loch or the German Bach. It is not like English ch in chair.

So chceš begins with that rough throaty sound:

• chceš ≈ kh-tsehsh (very approximate)

Also note:

• č is like ch in chair
• c is like ts
• š is like sh

So Czech spelling is very systematic, but the sounds may be unfamiliar at first.

The marks are important because they show different sounds.

In this sentence:

• š = sh
• ě changes the pronunciation of the consonant before it and is part of the normal Czech spelling system

So:

• chceš ends in š, pronounced sh
• knihovně has ně, which sounds roughly like nye

These marks are not optional decoration; they are part of the spelling and often change pronunciation and meaning.

Grammatically, that is a helpful way to understand the Czech structure, but it is not how you should translate it into natural English.

• Czech: Kolik knih
• literal grammatical idea: how many of books
• natural English: how many books

So yes, the genitive plural often corresponds to an of-idea in grammar explanation, but the real translation into English is simply how many books.