Learn Hardcore Czech: Moje dcera je v knihovně každý týden, protože je tam tichý pokoj na čtení. - My daughter is in the library every week because there is a quiet room for reading.

In Czech, the subject of the sentence (the “doer” of the verb) is usually in the nominative case.
Here, Moje dcera is the subject of the verb je (“is”), so dcera must be nominative: (ta) dcera → Moje dcera.

Other forms of dcera for comparison:

Nominative: dcera (subject) – Moje dcera je v knihovně.
Accusative: dceru (direct object) – Vidím svoji dceru.

Why is it Moje dcera and not Má dcera?

Both Moje dcera and Má dcera are grammatically correct and mean “my daughter”.

Moje = the long form of the possessive adjective
Má = the short form

Differences:

Moje dcera is neutral, slightly more common in everyday speech.
Má dcera sounds a bit more formal, emphatic, or literary. You might meet it more in writing, stories, or when the speaker wants to stress my.

So, in ordinary conversation, Moje dcera is very natural here.

Why is it v knihovně and not v knihovna?

Knihovna is a noun that changes its ending according to case.
After the preposition v meaning “in/at” (location), Czech uses the locative case.

Declension of knihovna (singular, feminine):

Nominative (dictionary form): knihovna – Ta knihovna je velká. (The library is big.)
Locative: knihovně – Jsem v knihovně. (I am in/at the library.)

In your sentence, “my daughter is in the library”, so v knihovně (locative) is required.

Why do we use v and not na for “in/at the library”? Could I say na knihovně?

For library, Czech uses v knihovně (literally “in the library”) for being inside or at the place.

v + locative = “in / inside / at” something enclosed or considered as a space:
- v knihovně – in/at the library
- v pokoji – in the room
- v obchodě – in/at the shop

Na knihovně would mean “on the library” (physically on top of the building) and is not what you want for “at the library”.

So:

Je v knihovně. = She is in/at the library.
Sedí na knihovně. = She is sitting on the (piece of furniture called) bookcase.

What case is knihovně exactly, and when do we use that case?

Knihovně is in the locative singular.

The locative is used:

Almost always with certain prepositions, especially:
- v / ve – in
- na – on (location)
- o – about (talking about something)
Only to express ideas like:
- location: v knihovně, na stole
- topic of talk: mluvíme o knihovně (we talk about the library)

You cannot use locative without a preposition in modern Czech.

Why is it každý týden and not každou týden?

The word týden (“week”) is masculine inanimate (ten týden).
The adjective/pronoun každý (“every”) must agree in gender, number, and case with the noun it modifies.

Here:

Gender: masculine inanimate → každý týden
Case: accusative, used for time expressions (how often? when?) → the form happens to match the nominative for this gender.

Každou is feminine accusative and would be used with a feminine noun, for example:

každou neděli – every Sunday (neděle = feminine)

What case is týden in každý týden, and why?

Týden is in the accusative singular.

Czech often uses the accusative for adverbial expressions of time, especially for how often or when something happens:

každý den – every day
každý měsíc – every month
minulý rok – last year
celý týden – the whole week

So každý týden is literally "every week" in the accusative, acting as a time expression: She is there every week.

Why is the verb je repeated? We have Moje dcera je v knihovně… protože je tam tichý pokoj… Is that normal?

Yes, that is completely normal and necessary.

There are two separate clauses, each with its own verb je (“is”):

Moje dcera je v knihovně každý týden
– My daughter is in the library every week.
protože je tam tichý pokoj na čtení
– because there is a quiet room for reading there.

In the second clause, je works like English “there is”:
je tam tichý pokoj… = there is a quiet room there…

Why is it je tam tichý pokoj and not tam je tichý pokoj?

Both je tam tichý pokoj and tam je tichý pokoj are grammatically correct.

The difference is mostly word order / emphasis:

Je tam tichý pokoj na čtení.
– Neutral; slight focus on the existence of such a room: There is a quiet room there for reading.
Tam je tichý pokoj na čtení.
– Slightly more emphasis on there (“in that place”): It’s there that there is a quiet room for reading (as opposed to somewhere else).

Czech word order is relatively flexible; you choose the order to highlight what is important in the sentence.

Why is it tichý pokoj and not tichá pokoj or tichém pokoji?

Pokoj (“room”) is masculine inanimate (ten pokoj).
The adjective tichý (“quiet”) must agree with pokoj in gender, number, and case.

So:

Masculine singular nominative: tichý pokoj
Feminine singular nominative would be: tichá (e.g. tichá místnost)
Locative masculine singular: tichém pokoji (e.g. v tichém pokoji – in a quiet room)

In your sentence, tichý pokoj is the subject complement of je (“there is a quiet room”), so it’s in nominative: “(a) quiet room exists there.”

What does na čtení literally mean, and why do we use na here instead of pro?

Na čtení literally means “for reading” or “intended for reading”.

Czech often uses na + accusative to express the purpose / function of an object or place:

pokoj na spaní – a room for sleeping
stůl na práci – a table for working
brýle na čtení – reading glasses

You could sometimes use pro čtení, but:

na čtení sounds more natural and idiomatic when you talk about the intended use of a room or object.
pro is more about benefit or recipient (“for someone”), or sometimes a more abstract “for the purpose of”, but with rooms and tools na is preferred.

So tichý pokoj na čtení is “a quiet room (meant) for reading.”

Why is čtení used instead of the verb číst?

Čtení is a verbal noun (a noun formed from a verb), similar to English “reading” used as a noun.

Verb: číst – to read
Verbal noun: čtení – reading (the activity)

Czech often uses these verbal nouns after prepositions like na, k, po, etc.:

místnost na spaní – a room for sleeping
čas na odpočinek – time for rest / resting
pokoj na čtení – a room for reading

Using the bare infinitive číst after na here would be ungrammatical; you need the noun form čtení.

Why is the conjunction protože followed by normal word order and not some inversion, like in German?

In Czech, protože (“because”) is a subordinating conjunction, but it does not cause verb-final word order like in German.

Main clause: Moje dcera je v knihovně každý týden,
Subordinate clause: protože je tam tichý pokoj na čtení.

The word order in the subordinate clause is still relatively flexible and generally S–V–O-like, similar to English. So:

protože je tam tichý pokoj na čtení is completely normal.
Putting je at the very end (protože tam tichý pokoj na čtení je) would sound unnatural.

Does je here mean “is” or “is being” (continuous)? How do Czechs show repeated actions like “every week”?

Czech present tense je simply means “is”; it doesn’t distinguish between simple and continuous like English does (is vs is being).

To show repeated / habitual action, Czech usually relies on:

adverbs or phrases of frequency/time, like:
- každý týden – every week
- často – often
- obvykle – usually

So Moje dcera je v knihovně každý týden naturally means:

My daughter is at the library every week / goes to the library every week, depending on context. The repetition comes from každý týden, not from a special verb form.