Common Mistakes: Wrong Case After Prepositions | Czech Grammar

This is the single most common error English speakers make in Czech, and it shows up in almost every sentence until you fix the underlying habit. In English, a preposition leaves the next word completely untouched: to Prague, with brother, to the doctor — the noun never changes shape. In Czech, every preposition forces the following noun into a specific case, and using the dictionary (nominative) form instead is a grammatical error a native speaker hears instantly. The good news: the fix is one mental adjustment, not a hundred separate rules.

Why English speakers get it wrong

English has essentially no case system left, so English prepositions are "case-neutral" — the word after to, with, from, or about looks identical no matter what. Your brain has learned that a preposition is just a little connecting word, and the noun stays put. You then carry that habit into Czech and reach for the form you looked up in the dictionary.

But the Czech dictionary form is the nominative, the case used mainly for the subject of a sentence. After a preposition, the noun is almost never the subject, so the nominative is almost always wrong. The mistake is not that you chose the wrong case by accident — it's that you didn't realize a choice was being made at all.

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Stop thinking of a Czech preposition as one word. Think of it as a word plus a case instruction. When you learn do, you don't learn "to" — you learn "to + genitive." Store them together and the endings follow automatically.

Each preposition owns its case

The crucial idea: the case is a fixed property of the preposition, not something you decide based on meaning. do always takes the genitive; s always takes the instrumental; k always takes the dative. There is nothing to weigh or guess — once you know which case the preposition demands, you simply put the noun in that case.

Jedu do Prahy.

I'm going to Prague. (do + genitive: Praha → Prahy)

Bydlím u babičky.

I live at grandma's. (u + genitive: babička → babičky)

The error English speakers produce is do Praha — the city name left in its naked dictionary form. To a Czech ear that is as jarring as I'm going to she sounds to you.

Genitive prepositions: do, z, od, u, bez

A large family of high-frequency prepositions governs the genitive: do (into/to), z/ze (from/out of), od (from a person/point), u (at, near), bez (without), vedle (next to). The genitive often ends in -y/-i for feminine nouns and -a/-u for masculine and neuter nouns.

Vrátil se z práce moc unavený.

He came back from work really tired. (z + genitive: práce → z práce)

Dám si kávu bez cukru.

I'll have a coffee without sugar. (bez + genitive: cukr → cukru)

To je dárek od mého bratra.

That's a present from my brother. (od + genitive: bratr → bratra)

The full system of genitive-governing prepositions is laid out on the genitive prepositions page.

Instrumental prepositions: s/se

s (with) governs the instrumental case — the case that, on its own, expresses the means or accompaniment of an action. The instrumental typically ends in -em (masculine), -ou (feminine), and -em (neuter).

Jdu do kina s bratrem.

I'm going to the cinema with my brother. (s + instrumental: bratr → bratrem)

Mluvila jsem se sestrou celý večer.

I talked with my sister all evening. (se + instrumental: sestra → sestrou)

The classic learner error is s bratr — with brother translated word-for-word, leaving the noun in the nominative. Note also that s swells to se before an awkward consonant cluster (se sestrou), but the case it demands never changes.

Dative prepositions: k/ke

k/ke (to, toward — usually toward a person or place you approach) governs the dative. For masculine animate nouns the dative singular very often ends in -ovi.

Musím jít k doktorovi.

I have to go to the doctor. (k + dative: doktor → doktorovi)

Pojď ke mně blíž.

Come closer to me. (ke + dative pronoun: já → mně)

The error here is k doktor. Compare it with do + genitive (do nemocnice, "to the hospital") and you can see why storing the case with the preposition matters: both English *to*s, but Czech splits them across two different cases depending on the preposition.

na — when one preposition takes two cases

A handful of prepositions govern two cases, and the case you choose changes the meaning. na is the most important. With the accusative it means motion onto / to a destination; with the locative it means a static location on / at. Same preposition, different case, different meaning.

Preposition + case	Meaning	Example
na + accusative	motion — onto / to	na stůl, na poštu
na + locative	location — on / at	na stole, na poště

Polož ten talíř na stůl.

Put that plate on the table. (motion → accusative: na stůl)

Ten talíř je na stole.

That plate is on the table. (location → locative: na stole)

Musím zajít na poštu.

I have to pop over to the post office. (motion → accusative: na poštu)

Pracuje na poště už deset let.

She has worked at the post office for ten years. (location → locative: na poště)

Ask yourself a single question — am I moving toward it (accusative) or already there (locative)? — and the case follows. The same accusative-versus-locative split governs v, o, and za; it is covered in detail on the two-case prepositions page.

Quick reference: high-frequency prepositions by case

Memorize this small table and you cover the great majority of everyday sentences. (The two-case prepositions are marked; everything else governs a single, fixed case.)

Case	Common prepositions	Rough meaning
Genitive	do, z/ze, od, u, bez, vedle, podle	to/into, from, at, without, next to
Dative	k/ke, proti, díky, kvůli	toward, against, thanks to, because of
Accusative	pro, přes, skrz	for, across, through
Locative	v/ve, při, po, o (about)	in, during, after/along, about
Instrumental	s/se, nad, pod, před, za, mezi*	with, above, under, in front of, behind, between
Two cases	na, v, o, za, nad, pod, před, mezi	case depends on motion vs. location

The complete, organized map lives on the case-government map. For now, the table above plus one reflex — never leave the noun in the nominative after a preposition — will eliminate most of your errors.

Common mistakes

❌ Jedu do Praha.

Incorrect — do governs the genitive, so Praha must become Prahy.

✅ Jedu do Prahy.

I'm going to Prague.

❌ Jdu do kina s bratr.

Incorrect — s governs the instrumental, so bratr must become bratrem.

✅ Jdu do kina s bratrem.

I'm going to the cinema with my brother.

❌ Musím jít k doktor.

Incorrect — k governs the dative; the masculine animate dative here is doktorovi.

✅ Musím jít k doktorovi.

I have to go to the doctor.

❌ Ten talíř je na stůl.

Incorrect — this is a location, not motion, so na takes the locative: na stole.

✅ Ten talíř je na stole.

That plate is on the table.

❌ Vrátil se z práca.

Incorrect — the feminine noun práce is already in its base form; z + genitive keeps it as z práce, not z práca.

✅ Vrátil se z práce.

He came back from work.

Key takeaways

Czech prepositions are not case-neutral like English ones: each one forces a specific case on the following noun.
The dictionary form is the nominative, which is almost always wrong after a preposition.
Learn each preposition together with its case — do
- genitive, s
  - instrumental, k
    - dative — as a single unit.
A few prepositions (na, v, o, za, nad, pod, před, mezi) take two cases; choose accusative for motion toward, locative/instrumental for static location.
The one reflex that fixes most errors: after a preposition, the noun must change form — never leave it in the nominative.

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