Wh-questions ("who? what? where? why?") are how you pull specific information out of a conversation, and Czech has a tidy set of question words for them. Two things make this topic bigger than a vocabulary list. First, Czech splits the English "where?" into three different words depending on whether you mean being somewhere, going somewhere, or coming from somewhere. Second — and this is the deep point — the words for "who?" and "what?" change their form to match the grammatical case the rest of the sentence requires. Asking the question correctly means asking it in the right case.
The inventory
| Czech | English | Notes |
|---|---|---|
| kdo | who | declines for case |
| co | what | declines for case |
| kde | where (location) | "in what place" |
| kam | where to (direction) | "to what place" |
| odkud | where from (origin) | "from what place" |
| kdy | when | |
| jak | how | |
| proč | why | |
| kolik | how much / how many | followed by genitive |
| který | which | declines like an adjective |
| čí | whose | declines |
| jaký | what kind of | declines like an adjective |
Kdo to je?
Who is it?
Co děláš?
What are you doing?
Kam jdeš?
Where are you going? (to where)
Kolik to stojí?
How much does it cost?
Čí je to?
Whose is it?
The big point: kdo and co decline
This is the part English does not prepare you for. In English, "who" only ever changes to "whom" in formal writing, and "what" never changes at all. In Czech, kdo and co run through the full case system, and the form you choose must match what the verb or preposition needs.
| Case | "who" | "what" | Triggered by |
|---|---|---|---|
| Nominative (subject) | kdo | co | the doer / the topic |
| Genitive | koho | čeho | "of", many prepositions |
| Dative | komu | čemu | "to/for", giving verbs |
| Accusative (object) | koho | co | direct object |
| Locative | (o) kom | (o) čem | always with a preposition |
| Instrumental | kým | čím | "with/by", "s" |
The logic is simple once you see it: the question word stands in for the very noun you are asking about, so it has to wear the same case that noun would wear in the answer. If the verb takes a direct object, you ask with the accusative; if it takes "to someone," you ask with the dative.
Koho vidíš?
Whom do you see? (accusative — 'vidět' takes a direct object)
Komu to dáš?
To whom will you give it? (dative — the recipient)
S kým jdeš?
With whom are you going? (instrumental — required by the preposition 's')
O čem mluvíš?
What are you talking about? (locative — required by the preposition 'o')
Čeho se bojíš?
What are you afraid of? (genitive — 'bát se' governs the genitive)
Prepositions are an especially clear trigger, because each preposition locks a particular case. S/se ("with") forces the instrumental, so "who with?" is s kým. O ("about") forces the locative, so "what about?" is o čem. You will meet these pairings constantly; see Interrogative kdo / co for the full declension and The Seven Cases and Their Questions for how case questions organise the whole system.
The kde / kam / odkud trio
English uses one word, "where," for three different spatial relationships, and then patches the difference with extra prepositions ("where to," "where from"). Czech bakes the distinction straight into the question word:
- kde — location: where something is ("in what place")
- kam — direction: where something is going ("to what place")
- odkud — origin: where something comes from ("from what place")
Kde bydlíš?
Where do you live? (location — you ARE there)
Kam jdeš?
Where are you going? (direction — you're heading there)
Odkud jsi?
Where are you from? (origin)
The verb tells you which to use: a static verb (být "to be," bydlet "to live," zůstat "to stay") pairs with kde; a motion verb (jít "to go," jet "to drive," dát "to put") pairs with kam. Mixing them up — asking Kde jdeš? — is one of the most common beginner slips. The same three-way contrast shows up in answers too; see kde / kam / odkud adverbs.
Common Mistakes
❌ Kdo vidíš?
Incorrect — 'kdo' is nominative; a direct object needs the accusative 'koho'
✅ Koho vidíš?
Whom do you see?
❌ Kde jdeš?
Incorrect — 'jít' is motion, so it needs direction 'kam', not location 'kde'
✅ Kam jdeš?
Where are you going?
❌ S kdo jdeš?
Incorrect — the preposition 's' forces the instrumental, so it must be 's kým'
✅ S kým jdeš?
Who are you going with?
❌ Co mluvíš?
Incorrect for 'about what' — 'mluvit o' needs the locative 'o čem'
✅ O čem mluvíš?
What are you talking about?
❌ Komu to je?
Incorrect — 'whose' is 'čí', not the dative 'komu' ('to whom')
✅ Čí to je?
Whose is it?
Key Takeaways
- Learn the full set, but know that kdo, co, který, jaký, čí all decline.
- For kdo/co, choose the case the verb or preposition demands: koho/komu/kým, čeho/čemu/čím — never default to the nominative for every role.
- Prepositions lock the case: s kým (with whom), o čem (about what), čeho se bojíš (afraid of what).
- Czech has three "where" words: kde (location), kam (direction), odkud (origin) — chosen by the verb.
- kolik ("how much/many") is followed by the genitive: kolik lidí (how many people).
Now practice Czech
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Start learning Czech→Related Topics
- kdo and co: Who and WhatA2 — The pronouns kdo (who) and co (what) as both question words and relatives, with their full declension and their fixed singular agreement.
- Adverbs of Place: the kde / kam / odkud SystemA2 — Czech splits 'where' into location, direction, and origin — and 'here' into tady, sem, and odsud.
- The Seven Cases and Their QuestionsA1 — The names of the seven Czech cases and the question word that identifies each one.
- Word Order in QuestionsA1 — Czech forms questions without reordering words or adding an auxiliary — yes/no questions keep statement order plus rising intonation, and wh-questions front the question word with clitics still in second position.