Subordinate Clauses in Czech

In Brief

A Czech subordinate clause depends on another clause and is usually introduced by a word such as že (that), který (who/which), když (when/if), aby (so that), or protože (because). Czech normally places a comma at the boundary between the clauses, but it does not move the verb to the end. The relative pronoun který changes its ending according to gender, number, and its role inside the relative clause.

Overview

A clause is a group of words built around a verb. A main clause can stand as a sentence by itself; a subordinate clause adds information but depends on another clause. In Vím, že máš pravdu (“I know that you are right”), Vím is the main clause and že máš pravdu is the subordinate clause.

At B1, these structures let you move beyond short statements. You can report thoughts with že, identify people and things with který, locate events in time with když, express a purpose or desired outcome with aby, and give a reason with protože. English uses close equivalents, but there are important differences: Czech normally keeps že where English can omit “that,” puts commas around clause boundaries more consistently, and uses case endings on relative pronouns.

Czech word order remains fairly flexible inside a subordinate clause. There is no German-style rule that sends the verb to the end, and there is no English-style inversion in an embedded question. What does need special attention is the placement of short unstressed words such as se, si, and forms of být: these clitics (short words that lean on a neighboring stressed word) normally occupy the second position in their own clause.

How It Works

The five core connectors

Connector	Main job	Typical English equivalent	Example
že	statement, thought, knowledge, report	that	Myslím, že přijde.
který	identifies or describes a noun	who, which, that	kniha, kterou čtu
když	time or condition	when, whenever, if	Když mám čas, čtu.
aby	purpose, wish, request, intended result	so that, in order that	Přišel, aby pomohl.
protože	reason	because	Zůstal doma, protože pršelo.

The connector belongs to the subordinate clause. That matters when deciding where the comma goes and where second-position clitics belong.

Commas mark the clause boundary

Czech normally separates a subordinate clause from its main clause with a comma:

• Vím, že máš pravdu. — I know that you are right.
• Zůstanu doma, protože jsem nemocný. — I will stay home because I am ill.
• Když bude hezky, půjdeme ven. — When the weather is nice, we will go out.
• Ta žena, která čeká venku, je moje lékařka. — The woman who is waiting outside is my doctor.

If the subordinate clause comes first, place the comma after it. If a relative clause interrupts the main clause, use a comma on both sides. Unlike English, Czech generally also uses a comma before a relative clause that is essential for identifying the noun: Lidé, kteří tu pracují, mluví česky. Do not copy the English distinction between comma-free restrictive clauses and comma-marked nonrestrictive clauses.

A short expression is not automatically a clause. There is no comma in Přišel kvůli práci (“He came because of work”), because kvůli práci has no verb.

Clauses with že

Use že to introduce the content of a thought, statement, perception, or fact:

• Vím, že je doma. — I know that he is at home.
• Řekla, že nemá čas. — She said that she did not have time.
• Je dobře, že jsi přišel. — It is good that you came.

English often drops “that”: “I think she is right.” Standard Czech normally retains že: Myslím, že má pravdu. The word order after že is ordinary Czech clause order; the verb does not move to the end.

When the subordinate clause contains clitics, count positions again from the start of that clause. The connector commonly provides the first position:

• Vím, že se učíš. — I know that you are studying.
• Řekl, že mi zavolá. — He said that he would call me.
• Myslím, že jsem ho už viděl. — I think I have seen him before.

Relative clauses with který

A relative clause describes a noun already mentioned, called its antecedent (the noun the clause points back to). Který agrees with that noun in gender and number, but its case (the ending that shows its job in the sentence) is determined by what it does inside the relative clause.

Compare these forms referring to muž (“man”):

Role inside the relative clause	Czech phrase	Why this form?
subject	muž, který tu bydlí	The man performs the action, so nominative is used.
direct object	muž, kterého znám	I know the man, so accusative masculine animate is used.
after s	muž, se kterým pracuji	s (“with”) requires the instrumental case.
after o	muž, o kterém mluvím	o (“about”) requires the locative case.

Now compare feminine and neuter antecedents:

• žena, která tu bydlí — the woman who lives here
• žena, kterou znám — the woman whom I know
• město, které máme rádi — the city that we like
• knihy, které hledám — the books that I am looking for

A reliable method is to rebuild the relative clause as a simple sentence. For kniha, kterou čtu, start with Čtu knihu (“I am reading the book”). Knihu is accusative, so the feminine relative pronoun must also be accusative: kterou.

Prepositions stay directly before the relative pronoun: firma, pro kterou pracuji (“the company I work for”). English can leave a preposition at the end; Czech cannot say the equivalent of “the company which I work for” with pro stranded at the end.

Time and conditions with když

Když can mean “when,” “whenever,” or sometimes “if.” Context and the verb forms make the intended meaning clear:

• Když vařím, poslouchám rádio. — When/Whenever I cook, I listen to the radio.
• Když jsem přišel domů, zavolal jsem jí. — When I came home, I called her.
• Když budeš chtít, pomůžu ti. — If you want, I will help you.

Czech often uses a present-form perfective verb for a completed future event: Když přijdeš, zavolej mi (“When you arrive, call me”). Přijdeš looks like a present-tense form but has future meaning because přijít is perfective (it presents the arrival as a completed event).

For a single future event expected to happen, až is often more precise than když: Až přijdeš domů, zavolej mi (“Call me when you get home”). Use když readily for repeated events, past events, and conditions; learn the když–až contrast as a tendency rather than translating every English “when” automatically.

Purpose and desired outcomes with aby

Aby introduces something intended, wanted, requested, or necessary. Its form includes information about the person:

Person	Form	Example
já	abych	Musím odejít, abych stihl vlak.
ty	abys	Píšu ti, abys na to nezapomněl.
on/ona/ono	aby	Přišla, aby nám pomohla.
my	abychom	Šetříme, abychom mohli cestovat.
vy	abyste	Mluvte pomalu, abyste byli srozumitelní.
oni/ony/ona	aby	Zařídím to tak, aby mohli jít se mnou.

The verb after aby commonly appears as an -l form—the form also seen in the past tense—and agrees where relevant: abych přišel for a male speaker, abych přišla for a female speaker; abychom přišli for a mixed or all-male group, abychom přišly for an all-female group. Despite the form, abych přišel does not itself mean “I came”; the whole construction expresses a desired or intended event.

Use aby when the subordinate clause has its own stated or understood participant:

• Otevřel jsem okno, aby dovnitř proudil čerstvý vzduch. — I opened the window so that fresh air could flow in.
• Chci, abys přišel včas. — I want you to come on time.

When the same person performs both actions, Czech may prefer an infinitive for a simple purpose: Jdu nakoupit (“I’m going shopping / to shop”). An aby clause is useful when the purpose needs more detail, contrast, or a different subject.

Reasons with protože

Protože gives the cause or reason for the main clause:

• Nešel jsem ven, protože pršelo. — I did not go out because it was raining.
• Protože pršelo, zůstali jsme doma. — Because it was raining, we stayed home.

Write the ordinary conjunction protože as one word. The sequence proto, že is a different structure: proto means “for that reason,” and the following že clause explains it. For example, Udělal to proto, že potřeboval peníze means “He did it because he needed money,” with emphasis on the reason. This distinction matters in careful writing.

Examples in Context

Czech	English	Note
Vím, že máš pravdu.	I know that you are right.	že introduces known information.
Myslíš, že už dorazili?	Do you think they have arrived yet?	The whole že clause is part of a question.
Řekla mi, že se vrátí večer.	She told me that she would return in the evening.	se comes near the start of its own clause.
Muž, který tu bydlí, je lékař.	The man who lives here is a doctor.	který is the subject of the relative clause.
To je kolegyně, kterou jsem potkal v Brně.	That is the colleague I met in Brno.	kterou is feminine accusative. A male speaker says potkal.
Hledám dokument, o kterém jsme mluvili.	I am looking for the document we talked about.	o requires the locative kterém.
Když mám volno, jezdím na kole.	When I have time off, I cycle.	A repeated situation.
Když přijdeš dřív, můžeme zajít na kávu.	If you come earlier, we can go for coffee.	Here když has a conditional sense.
Až skončí schůzka, napíšu ti.	When the meeting ends, I will text you.	až marks an expected single future event.
Učím se, abych složil zkoušku.	I am studying to pass the exam.	Purpose; a male speaker uses složil.
Prosím vás, abyste chvíli počkali.	Please wait for a moment.	A polite request with abyste.
Zavřela dveře, aby nás nikdo nerušil.	She closed the door so that nobody would disturb us.	The purpose clause has a different subject.
Objednali jsme si taxi, protože už nic nejelo.	We ordered a taxi because nothing was running anymore.	protože gives the reason.
Protože jsem ztratil klíče, nemohl jsem otevřít dveře.	Because I had lost my keys, I could not open the door.	The reason clause comes first.

Common Mistakes

Omitting že because English can omit “that”

• Wrong: Myslím, má pravdu.
• Right: Myslím, že má pravdu.
• Why: English allows “I think she is right,” but Czech normally needs že to introduce the content clause.

Copying English comma rules for relative clauses

• Wrong: Lidé kteří tu pracují mluví česky.
• Right: Lidé, kteří tu pracují, mluví česky.
• Why: Czech marks the relative clause with commas even when it identifies which people are meant.

Choosing který only by the antecedent’s dictionary form

• Wrong: To je žena, který znám.
• Right: To je žena, kterou znám.
• Why: The antecedent žena is feminine, and the woman is the direct object of znám, so kterou is feminine accusative.

Leaving a preposition at the end

• Wrong: Firma, kterou pracuji pro, je česká.
• Right: Firma, pro kterou pracuji, je česká.
• Why: Czech puts the preposition before the relative pronoun. It does not strand it at the end as conversational English can.

Using aby without its personal ending

• Wrong: Učím se, aby složil zkoušku when the intended subject is “I.”
• Right: Učím se, abych složil zkoušku.
• Why: Use abych for “I,” and make the -l form agree with the speaker where necessary.

Putting a clitic too late in the subordinate clause

• Wrong: Vím, že učíš se česky.
• Right: Vím, že se učíš česky.
• Why: Se is a clitic and normally comes in the second-position cluster of its own clause, here directly after že.

Usage Notes

In everyday speech, že, protože, and když are extremely common. The basic punctuation rules still apply in writing, even when a speaker makes only a very slight pause. Do not decide commas by listening for pauses alone; identify the clauses and their verbs.

Colloquial Czech often uses invariant co where careful writing prefers a form of který: Ten kluk, co tam stojí... (“That boy who is standing there...”); film, co jsme viděli (“the film we saw”). This is natural in conversation, but který and its declined forms are safer in formal writing and make the grammatical relationship explicit. Co is standard, however, in combinations such as to, co (“what/that which”) and všechno, co (“everything that”): Řekni mi všechno, co víš.

English speakers should also resist moving the Czech verb to match English question patterns. A direct question is Kde bydlí? (“Where does he live?”), and an embedded question keeps the same core order: Nevím, kde bydlí (“I don’t know where he lives”). Czech does not add an equivalent of English “do,” nor does it require a special embedded-question inversion.

The fragment Muž, který tu bydlí means “the man who lives here,” but it is not normally a complete sentence: the noun phrase still needs a main-clause verb, as in Muž, který tu bydlí, je architekt. Fragments are possible as headings, labels, or deliberate conversational replies, but build complete sentences in neutral prose.

Beyond the Basics: Advanced Use

Tense follows meaning, not automatic backshift

Czech does not apply the automatic sequence-of-tenses pattern often taught for English reported speech. After a past reporting verb, choose the tense that expresses the intended time:

• Řekl, že je unavený. — He said that he is/was tired; the present can present the tiredness as still current or simultaneous from the speaker’s viewpoint.
• Řekl, že byl unavený. — He said that he had been/was tired; byl explicitly places it in the past.
• Řekl, že přijde. — He said that he would come; the perfective present-form přijde has future meaning.

Context often resolves the exact English translation. This becomes especially important in indirect speech.

Relative words beyond který

For people, kdo appears in patterns without a simple noun antecedent: Kdo chce, může přijít (“Whoever wants may come”) and Ten, kdo chce, může přijít (“The person who wants may come”). For things or whole ideas, to, co is common: To, co říkáš, je důležité (“What you are saying is important”).

Careful and formal Czech also has possessive relative forms such as jehož (“whose,” referring to a masculine or neuter singular possessor) and jejíž (“whose,” referring to a feminine singular possessor): autor, jehož knihu čtu (“the author whose book I am reading”). These forms have their own agreement patterns and are best studied with relative pronouns as a separate topic.

Several subordinate clauses can be nested

A clause can contain another subordinate clause:

Vím, že muž, který tu bydlí, pracuje v nemocnici. “I know that the man who lives here works in a hospital.”

Here the který clause sits inside the larger že clause. First identify the verb of each clause—vím, bydlí, pracuje—then match every connector and comma boundary. This clause-by-clause method scales to longer formal sentences.

Coordinated connectors can affect punctuation

When two subordinate clauses of the same type are joined by a single a or nebo, Czech often does not put a comma immediately before that conjunction: Vím, že přijde a že nám pomůže (“I know that he will come and that he will help us”). More complex combinations can require different punctuation. At an advanced level, analyze which clauses are coordinated rather than inserting a comma mechanically before every connector.

Practice Tips

1. Mark the clause skeleton. In a paragraph, underline every finite verb (a verb marked for person or tense), circle že, který, když, aby, protože, and draw a line at each clause boundary. Then check the commas.
2. Transform simple sentences into relative clauses. Start with Znám tu ženu and Ta žena pracuje tady. Combine them as Znám tu ženu, která tady pracuje. Repeat with the noun as an object or after a preposition so that který changes case.
3. Build contrast pairs. Say one reason with protože, one purpose with aby, and one time condition with když: Zůstávám doma, protože prší; Zůstávám doma, abych pracoval; Když prší, zůstávám doma. This prevents connectors with different logical jobs from blending together.

Related Concepts

• Prerequisite: Reflexive Verbs — helps with second-position se and si inside subordinate clauses.
• Next step: Relative Pronouns — develops the full declension and use of který and related forms.
• Next step: Indirect Speech — expands reporting with že, tense choices, questions, and commands.
• Advanced: Complex Sentence Structures — combines coordination, nesting, punctuation, and stylistic clause patterns.