Learn Hardcore Czech: Můj otec říká, že krásný den je ten, kdy je celá rodina zdravá a šťastná. - My father says that a beautiful day is when the whole family is healthy and happy.

Můj otec říká… = My father says… or My father always says… (a repeated, typical statement)
Můj otec řekl… = My father said… (a specific occasion in the past)

In English we might still say “My father always said…”, using past, but Czech prefers present for things that are still considered true or typical now.

Why do we need že in říká, že krásný den je ten…? Could we leave it out?

Že is a conjunction meaning “that” which introduces an entire subordinate clause – what the father says.

Můj otec říká, že… = My father says that…

Unlike English, where “that” can often be omitted (“My father says (that) a beautiful day is…”), in Czech you cannot simply drop že in this sentence.
Without že, the sentence would sound broken or confusing:

✗ Můj otec říká krásný den je ten… – ungrammatical.

Why is it krásný den and not krásní den or krásného dne?

Den is masculine inanimate, nominative singular (ten den).

The adjective krásný agrees with den in:

gender: masculine
number: singular
case: nominative (it’s the subject complement, “the day is beautiful”)

So:

krásný den – correct (nom. masc. sg.)
krásní – masc. animate plural (for people, e.g. krásní muži)
krásného dne – genitive singular (e.g. během krásného dne – during a beautiful day)

Here, the basic dictionary form krásný den is needed.

What is the function of ten in krásný den je ten, kdy…? Why is it there?

Ten is a demonstrative pronoun, similar to “the one” in English.

The structure is:

krásný den je ten, kdy…
literally: “a beautiful day is the one when…”

So:

krásný den = “a beautiful day”
ten = “the one (that/which/when)…”

You could also say:

Krásný den je, když je celá rodina zdravá a šťastná.
(A beautiful day is when the whole family is healthy and happy.)

Both are possible, but ten, kdy… sounds a bit more formal or emphatic: “the kind of day that…”

Why is den not repeated after ten? Why don’t we say ten den, kdy…?

It could be repeated, but it doesn’t have to be.

krásný den je ten, kdy… – a beautiful day is the one when…
krásný den je ten den, kdy… – a beautiful day is the day when… (also correct)

Czech often avoids repetition if the noun is obvious. Ten alone already clearly refers back to den, so den can be omitted without any confusion.

What is the difference between kdy and když here? Could we say …ten, když je celá rodina…?

In this sentence kdy works like a relative adverb, similar to “when” in:

the day *when the whole family is healthy and happy*

Kdy connects to den (day).

Když is a subordinating conjunction meaning “when / whenever / if” in a more general temporal sense, without directly referring back to a specific noun like “day”.

So:

ten, kdy je celá rodina zdravá a šťastná – the one when the family is healthy and happy (relative clause)
Když je celá rodina zdravá a šťastná, je to krásný den. – When the whole family is healthy and happy, it’s a beautiful day. (general “when” clause)

…ten, když… sounds wrong in standard Czech here; with ten, you need kdy, not když.

Why is celá rodina singular, but in English we might say “the whole family are healthy”?

In Czech, rodina is grammatically singular feminine.

celá rodina = “the whole family” (singular)
verbs and adjectives that refer to rodina are also singular feminine:
- je zdravá, je šťastná

So grammatically, Czech treats rodina like “it”, not like “they”.
English often treats “family” as a group of people and may use a plural verb (the family are…), but Czech sticks to the singular form.

Why are the adjectives zdravá and šťastná in the -á form?

They agree with rodina, which is feminine singular, nominative.

rodina – fem. sg. nominative
zdravá – fem. sg. nominative
šťastná – fem. sg. nominative

In Czech, predicative adjectives (after je, “is”) still agree in gender, number and case with the noun:

Rodina je zdravá. – The family is healthy.
Rodiny jsou zdravé. – The families are healthy. (fem. pl.)

So zdravá a šťastná is the correct form here.

Could the word order be …kdy celá rodina je zdravá a šťastná instead of kdy je celá rodina…?

It’s technically possible, but kdy je celá rodina zdravá a šťastná is the most natural and neutral order.

kdy je celá rodina zdravá a šťastná – very natural
kdy celá rodina je zdravá a šťastná – possible, but the verb je pushed later can sound slightly emphatic or stylistically marked.

In spoken and standard written Czech, the normal pattern in such a clause is: [kdy] + [verb] + [subject] + [rest] → kdy je celá rodina zdravá a šťastná

Why is there a comma before že and also a comma before kdy?

Czech punctuation rules require commas before most subordinate clauses:

Comma before že
- Můj otec říká, že…
  The part že krásný den je ten, kdy… is a subordinate clause (object clause of “says”), so a comma is obligatory.
Comma before kdy
- …den je ten, kdy je celá rodina…
  Here kdy je celá rodina… is a relative clause describing ten (den), so again a comma is used.

Unlike English, where commas can be more flexible, Czech is quite strict about putting commas before subordinating conjunctions like že, kdy, když, protože etc.

Could we omit můj and just say Otec říká, že…?

Yes, you can.

Můj otec říká, že… – My father says that…
Otec říká, že… – Father says that… / Dad says that…

Adding můj makes it explicitly “my father”.
Without můj, it can still be understood as “(my) father” from context, similar to how in English people sometimes say “Father says…” when it’s obvious they mean their own father.

Why is it můj otec and not moje otec?

Possessive pronouns also agree in gender, number and case with the noun they modify.

otec is masculine singular (nominative).
The correct masculine form of můj in nominative singular is můj (not moje).

Forms:

můj otec – my father (masc. sg.)
moje matka – my mother (fem. sg.)
moje auto – my car (neuter sg.)

So můj otec is the correct combination.

Is there any difference in meaning if we say šťastná a zdravá instead of zdravá a šťastná?

Grammatically, both orders are correct and the meaning stays essentially the same: the family is healthy and happy.

zdravá a šťastná
šťastná a zdravá

The choice of order is mostly stylistic and about natural flow. Many speakers would spontaneously say zdravá a šťastná, but reversing them doesn’t change the logical content.