Learn Hardcore Czech: Moje maminka by byla ráda, kdybych dnes zůstal doma. - My mom would be happy if I stayed at home today.

Rád / ráda / rádo / rádi is a special word in Czech that often means glad / pleased / happy to. It behaves like an adjective and agrees with the subject’s gender and number:

masculine singular: rád
feminine singular: ráda
neuter singular: rádo
plural (mixed / masc. animate): rádi
plural (fem. or non‑animate): rády

Here the subject is maminka (feminine singular), so you must say ráda:

Moje maminka by byla ráda… – My mum would be glad…
Můj tatínek by byl rád… – My dad would be glad…

Šťastný / šťastná means happy in a stronger, more emotional sense (happy, delighted).
Být rád / ráda is usually milder: to be glad / pleased / would appreciate it.

So:

Moje maminka by byla ráda, kdybych dnes zůstal doma.
= My mum would be glad / pleased if I stayed home today.
Moje maminka by byla šťastná, kdybych dnes zůstal doma.
= My mum would be (really) happy if I stayed home today. (stronger emotion)

What is the difference between maminka and matka? Is Moje matka by byla ráda… also correct?

Both are grammatically correct, but they feel different.

maminka – affectionate, informal, like mum / mommy
má matka / moje matka – neutral to quite formal, often used in official language, writing, or when you want emotional distance; can sound cold or harsh in everyday speech

Native speakers usually say:

Moje maminka by byla ráda… – normal, warm, everyday Czech

You can say Moje matka by byla ráda…, but in many contexts it will sound stiff or emotionally distant, unless that is what you want.

How does kdybych work? Why is it one word and not kdyby + bych?

Kdybych corresponds roughly to “if I …” in an unreal / hypothetical situation.

kdy = when
by = conditional particle
ch = the I ending from bych (I would)

Historically it comes from kdy + by + ch, but in modern Czech it is written and treated as one word: kdybych.

Forms:

kdybych – if I …
kdybys – if you (sg.) …
kdyby – if he / she / it / they … (context decides)
kdybychom – if we …
kdybyste – if you (pl. / formal) …

In your sentence:

kdybych dnes zůstal doma = if I stayed home today

You cannot split kdybych as kdy by(ch) in normal modern Czech spelling; you just write kdybych.

Why is zůstal (a past tense form) used for something that hasn’t happened yet?

Czech uses past tense forms together with the conditional to talk about unreal or hypothetical situations, very similar to English:

English: If I stayed home, my mum would be glad.
Czech: Kdybych dnes zůstal doma, moje maminka by byla ráda.

Here:

zůstal is the past participle of zůstat (to stay)
together with bych (inside kdybych) it forms a conditional: if I stayed (hypothetically)

So even though zůstal looks like past, in this structure it is “if I stayed” / “if I were to stay”, not real past time.

Does zůstal change if the speaker is female? How would a woman say this sentence?

Yes, zůstal agrees with the speaker (já) in gender.

a man says:
Moje maminka by byla ráda, kdybych dnes zůstal doma.
a woman says:
Moje maminka by byla ráda, kdybych dnes zůstala doma.

What changes:

zůstal (masc.) → zůstala (fem.)

What doesn’t change:

by byla ráda – this part agrees with maminka, which is always feminine, regardless of who is speaking.

Can I change the word order, for example Moje maminka by byla ráda, kdybych zůstal dnes doma or Dnes by moje maminka byla ráda, kdybych zůstal doma?

Yes, Czech word order is quite flexible. All of these are grammatically fine:

Moje maminka by byla ráda, kdybych dnes zůstal doma. (neutral)
Moje maminka by byla ráda, kdybych zůstal dnes doma. (slightly more focus on staying today at home)
Dnes by moje maminka byla ráda, kdybych zůstal doma. (emphasis on today – maybe on other days she wouldn’t care as much)

The meaning stays almost the same; you just shift the emphasis:

Words moved toward the beginning of the clause are more contrastive / emphasized.
But keep the core structures together:
- by byla ráda (don’t separate by far from byla)
- kdybych zůstal / zůstala (keep kdybych with its verb)

Why is there a comma before kdybych?

Because kdybych dnes zůstal doma is a subordinate clause (an if‑clause).

Czech almost always separates subordinate clauses introduced by words like kdyby, když, protože, že, aby with a comma.

So you get:

Moje maminka by byla ráda, kdybych dnes zůstal doma.
Kdybych dnes zůstal doma, moje maminka by byla ráda.

In both directions, the main clause and the kdybych‑clause are divided by a comma.

Could I say Moje maminka by chtěla, abych dnes zůstal doma instead? What’s the difference in meaning?

Yes, you can, but the nuance changes.

Moje maminka by byla ráda, kdybych dnes zůstal doma.
- literally: My mum would be glad if I stayed home today.
- focuses on her feeling / pleasure
- sounds a bit softer, more like: She would appreciate it if…
Moje maminka by chtěla, abych dnes zůstal doma.
- literally: My mum would want (me) that I stay home today.
- focuses on her wish / desire
- can sound more direct, closer to: She would like me to stay home or She wants me to stay home.

So:

by byla ráda, kdybych… – emphasizes she would be pleased
by chtěla, abych… – emphasizes she (would) wants this to happen

Why do we say doma and not something like v domě?

Because doma means “at home”, your home, in general.

doma = at home (where you live, without specifying the building)
v domě = in (a) house / in the building (more literal, could be any house)

In English we say stay home or stay at home, not usually stay in the house unless we really mean inside the physical building.

So:

zůstat doma ≈ to stay home
zůstat v domě ≈ to stay in the house (building) – more concrete, used in specific contexts, stories, descriptions.

Where does bych normally go? Could I say kdyby dnes bych zůstal doma?

No, kdyby dnes bych zůstal doma is wrong in standard Czech.

The rule: words like bych, bys, by, bychom, byste are clitics. They usually stand in the second position in the clause, and after kdyby they fuse into one word: kdybych, kdybys, kdyby…

Correct patterns:

Kdybych dnes zůstal doma, moje maminka by byla ráda.
Dnes kdybych zůstal doma, moje maminka by byla ráda.
Dnes bych zůstal doma.
Já bych dnes zůstal doma.

Incorrect or very unnatural:

*Kdyby dnes bych zůstal doma.
*Kdyby zůstal bych doma.

So in your sentence, just remember:

kdybych + past tense is a solid pair: kdybych dnes zůstal / zůstala doma

How can I make similar sentences in Czech, like My dad would be happy if…?

You can copy the same structure:

[subject] + by byl / byla / bylo / byli rád / ráda / rádi, kdyby… + past tense

Examples:

Můj tatínek by byl rád, kdybych mu zavolal.
- My dad would be happy if I called him. (male speaker)
Můj tatínek by byl rád, kdybych mu zavolala.
- same, female speaker
Moji kamarádi by byli rádi, kdybys přišel.
- My friends would be happy if you (male) came.
Moje kamarádky by byly rády, kdybys přišla.
- My (female) friends would be happy if you (female) came.
Rodiče by byli rádi, kdybych přišel / přišla včas.
- My parents would be happy if I came on time.

So the recipe is:

choose the right form of být in the conditional (by byl / byla / bylo / byli)
choose the matching form of rád / ráda / rádi for the subject
add kdybych / kdybys / kdyby…
use the past form of the verb for the hypothetical action.