Learn Hardcore Czech: Když je jídlo levné, moje rodina je šťastná.

Až – when in the sense of “once/after something happens in the future” (more one-time and future-oriented).
- Až bude jídlo levné, moje rodina bude šťastná. – Once the food is cheap, my family will be happy.
Jestli / pokud – mostly if (more clearly conditional, not just temporal).
- Jestli bude jídlo levné, moje rodina bude šťastná. – If the food is cheap, my family will be happy.

In your sentence, když presents a general situation: whenever food is cheap, the family is happy.

Why is there a comma between Když je jídlo levné and moje rodina je šťastná?

Czech uses commas to separate main clauses from subordinate clauses much more consistently than English.

Když je jídlo levné, = subordinate clause (introduced by když)
moje rodina je šťastná. = main clause

Rule of thumb: in Czech, you normally put a comma between a když-clause and the rest of the sentence, regardless of the order:

Když je jídlo levné, moje rodina je šťastná.
Moje rodina je šťastná, když je jídlo levné.

Both need the comma.

Why is je used twice? Could you say just Když je jídlo levné, moje rodina šťastná?

You need je twice here. Czech normally requires the verb být (je = is) in both clauses:

jídlo je levné – food is cheap
moje rodina je šťastná – my family is happy

The shortened version moje rodina šťastná (without je) is not standard in this kind of neutral sentence. You might see similar omissions in headlines or very telegraphic style, but in normal speech and writing, keep je in both places:

Když je jídlo levné, moje rodina je šťastná. ✔️
Když je jídlo levné, moje rodina šťastná. ❌ (sounds broken in standard Czech)

Why is jídlo (food) treated as neuter, and why does levné end with -é?

Jídlo is a neuter noun in Czech (most nouns ending in -o are neuter). Adjectives must agree with the noun in gender, number, and case.

So for neuter singular nominative:

levné jídlo – cheap food
čerstvé ovoce – fresh fruit
dobré víno – good wine

The pattern for nominative singular:

Masculine inanimate: levný stůl (cheap table)
Masculine animate: levný pes (cheap dog – silly example, but grammatically fine)
Feminine: levná kniha (cheap book)
Neuter: levné jídlo (cheap food)

In the sentence, je jídlo levné – the predicate adjective levné still agrees with jídlo (neuter singular).

Why is rodina singular in Czech, even though in English we might say “my family are happy”?

In Czech, rodina (family) is grammatically feminine singular, and verbs normally agree with that grammatical form:

Moje rodina je šťastná. – literally My family is happy.

Czech focuses on grammatical number here (one family as a unit), not on the fact that it consists of several people. So:

rodina je (family is)
skupina je (group is)
firma je (company is)

You very rarely see something like moje rodina jsou šťastní, and it sounds odd or dialectal. Standard Czech keeps rodina with je and a singular feminine adjective: šťastná.

Why is it moje rodina, not můj rodina?

The possessive pronoun must agree with the gender and number of the noun it modifies.

můj is masculine singular (for masculine nouns like můj bratr – my brother).
moje is used for feminine and neuter nouns in the basic nominative form:
- moje rodina – my family (feminine)
- moje sestra – my sister (feminine)
- moje auto – my car (neuter)

So:

můj otec – my father (masc)
moje matka – my mother (fem)

There is also a shorter, more formal/literary feminine form má:

má rodina – my family

So both moje rodina and má rodina are correct; moje is more neutral and frequent in modern speech.

Can I switch the clause order and say Moje rodina je šťastná, když je jídlo levné? Does it change the meaning?

Yes, you can switch the order:

Když je jídlo levné, moje rodina je šťastná.
Moje rodina je šťastná, když je jídlo levné.

In this case, the meaning is essentially the same. The difference is about emphasis and rhythm:

Starting with Když je jídlo levné slightly emphasizes the condition.
Starting with Moje rodina je šťastná emphasizes the result/state, then explains when.

Both are natural and correct. The comma is required in both.

Does když je jídlo levné, moje rodina je šťastná refer to the present only, or can it mean the future like in English “when the food is cheap, my family will be happy”?

In Czech, the present tense is often used for:

general truths
regular, repeated situations
and also future situations introduced by když

So:

Když je jídlo levné, moje rodina je šťastná.
- As a general rule: whenever food is cheap, my family is (or gets) happy.
- In some contexts, it can also be understood as: when the food is cheap (in the future), my family will be happy.

If you really want to highlight a one-time future event, you can use the future:

Až bude jídlo levné, moje rodina bude šťastná. – Once the food is cheap, my family will be happy.

But with když, using present + present is very common and can include future meaning from context.

Why is jídlo in this exact form? Which case is it, and why?

Jídlo here is in the nominative singular. Nominative is the default case used for the subject of the sentence and also for the complement in X is Y structures:

jídlo je levné – food is cheap
- jídlo (subject, nominative)
- levné (predicate adjective, nominative, agreeing with jídlo)

Similarly in the second clause:

moje rodina je šťastná
- rodina (subject, nominative feminine singular)
- šťastná (predicate adjective, nominative feminine singular)

You only see other cases (accusative, genitive, etc.) when the noun is used in other roles, e.g.:

Kupujeme levné jídlo. – We buy cheap food. (jídlo is object, accusative)

How do you pronounce šťastná and jídlo? The consonant clusters look tricky.

Approximate pronunciation (using English-friendly hints):

jídlo – [yeed-lo]
- í is a long ee sound
- dl is pronounced together, like in English “medley” but without the vowel between d and l
šťastná – [shtyas-tna] (one smooth word)
- š = English sh
- ť is a “soft” t, a bit like ty in “tube” in some accents; palatalized
- šť together is close to sht, but the tongue is more forward/soft
- á is a long a like in “father”

Stressed syllable is typically the first syllable in Czech words, so:

JÍ-dlo
ŠŤAS-tná

Could the sentence also use jestli instead of když, like Jestli je jídlo levné, moje rodina je šťastná? Would that change the meaning?

You can say:

Jestli je jídlo levné, moje rodina je šťastná.

This is grammatically correct, but the nuance changes:

když – tends to sound more like a regular or expected situation: when(ever) food is cheap…
jestli – sounds more like a condition that may or may not be true: if food is cheap…

So když is more natural for general habits or typical reactions, while jestli highlights the uncertainty of the condition.

Could levné go before jídlo, like Když je levné jídlo, moje rodina je šťastná?

You could say:

Když je levné jídlo, moje rodina je šťastná.

But notice the meaning shift:

Když je jídlo levné – when the food (that we are talking about) is cheap.
Když je levné jídlo – when there is cheap food / when cheap food exists (e.g., on sale somewhere).

So:

Když je jídlo levné describes a property of a specific jídlo (food) you have in mind.
Když je levné jídlo sounds more like when cheap food is available. Both are correct, but they answer slightly different questions.