Localize Cs

Translate to Czech (cs) — High-Fidelity Skill

Scope & Variants

Czech is a single standard target — Modern Standard Czech (spisovná čeština). No regional split for product UI:

| Locale | Notes | |--------|-------| | cs / cs-CZ | Standard Czech (Czechia). Default and only target. |

Note on "Czech Republic" vs "Czechia": the country's official short name is now Česko / Czechia (adopted 2016). Use the short form in UI; reserve Česká republika for formal/legal contexts.

Practical reality: Czech translation has one target. The defining quality concern is disambiguating from Slovak, which is structurally similar but lexically distinct.

Czech vs Slovak — distinct West Slavic languages, often confused

Czech and Slovak are mutually intelligible (especially in writing) but they are separate languages with distinct vocabulary, distinct alphabets, and distinct grammar in places. This skill is the mirror partner to localize-sk.

Czech has 3 letters Slovak doesn't:

| Czech | Used for | Slovak equivalent | |-------|----------|-------------------| | ě | /je/ or palatalizing previous consonant | not used (Slovak uses e or different forms) | | ř | /rž/ (uniquely Czech phoneme) | not used (Slovak has plain r) | | ů | long /u:/ (alternant of ó from morphological change) | uses ú instead |

Slovak has 5 letters Czech doesn't: ľ ĺ ŕ ô ä. Any of these appearing in Czech text means a Slovak word leaked in.

Common Czech vs Slovak vocabulary (the surface markers a translation must NOT mix):

| English | ✓ Czech | ✗ Slovak (do NOT use in cs) | |---------|---------|-----------------------------| | file | soubor | súbor | | folder | složka | zložka / priečinok | | user | uživatel | používateľ | | settings | nastavení | nastavenia | | browser | prohlížeč | prehliadač | | but | ale | ale (same) | | because | protože | pretože | | yes | ano | áno (with diacritic) | | no | ne | nie | | month | měsíc | mesiac | | Monday | pondělí | pondelok | | Tuesday | úterý | utorok | | only | jen / pouze | len / iba | | also | také / taky | tiež / aj | | can | moci / moct | môcť | | want | chtít | chcieť | | see | vidět | vidieť | | do | dělat | robiť | | big | velký | veľký |

If a Czech translation contains súbor, používateľ, nastavenia, prehliadač, áno, mesiac, pondelok, robiť, vidieť, or any of the letters ľ ĺ ŕ ô ä — IT'S WRONG (Slovak leaked in). Fix to the Czech equivalents.

---

Register Auto-Detection (Apply Before Translating)

Czech has a strong T-V distinction (Vy/ty — called "vykání" vs "tykání"). Auto-detect from source:

| Source signal | Target register | |---------------|-----------------| | Casual / conversational / personal (Hey!, contractions, emoji, marketing voice, gaming, social) | Informal (ty / tykání) — ty lowercase, 2nd-person sg. verb endings (-š: můžeš, vidíš), familiar imperative (singular: vyber, klikni, otevři). | | Neutral product UI / docs / consumer software (DEFAULT) | Formal (Vy / vykání) — Vy capitalized for direct address, 2nd-person pl. verb endings (-te: můžete, vidíte), polite imperative (-te/-ete: vyberte, klikněte, otevřete). Possessive Váš/Vaše capitalized. | | Legal / banking / government / enterprise B2B | Formal (Vy) elevated — same Vy form but full constructions, no contractions, prefer impersonal reflexive (Provádí se), native vocabulary. |

Hard rule: never mix levels in one text. A string with Vy můžete (formal verb) and tvoje nastavení (informal possessive) is broken.

Capitalization rule for Vy: Vy / Váš / Vaše / Vám / Vás are capitalized in direct second-person address.

Default for software UI: Vy (formal) unless brand voice is explicitly youth/casual.

---

Critical Hard Rules (Severity ≥ 2.0 — Auto-Fail If Wrong)

1. Czech identity — NOT Slovak (severity 2.5)

Documented above. Check for Slovak letters (ľ ĺ ŕ ô ä) and Slovak vocabulary.

2. Word integrity — verb prefixes NEVER split (severity 3.0)

Czech verbs with prefixes are single words. Splitting them is a critical error.

| ✗ Wrong (split) | ✓ Correct (joined) | |-----------------|---------------------| | pře vést | převést (to transfer) | | pro vést | provést (to execute) | | vy konat | vykonat (to perform) | | na hrát | nahrát (to upload / record) | | pře nést | přenést (to transfer) | | od eslat | odeslat (to send out) | | při jmout | přijmout (to accept) | | za hájit | zahájit (to begin) |

Reflexive se / si is SEPARATE clitic — not attached to verb in writing. přihlásit se, registrovat se, zabývat se. Writing přihlásitse is wrong.

3. Czech diacritics — preserve all (severity 2.5)

Czech uses: á č ď é ě í ň ó ř š ť ú ů ý ž. Stripping any is a critical readability failure. Especially:

• ě (mě, tě, pět, dělat) — palatalizing e.
• ř (říjen, řeka, řekl) — uniquely Czech sound.
• ů (dům, stůl, obrátit) — long u with marker.

| ✗ Stripped | ✓ Correct | |------------|-----------| | uzivatel | uživatel | | nastaveni | nastavení | | prohlizec | prohlížeč | | reka | řeka | | dum | dům |

4. Seven-case system — Czech retains active vocative (severity 2.5)

Czech uses all 7 Slavic cases, INCLUDING the vocative (unlike Slovak which merged it into nominative). Every noun, adjective, and pronoun declines.

| Case | Question | Use | Example (m. anim. "uživatel") | Example (f. "aplikace") | |------|----------|-----|-------------------------------|--------------------------| | Nominativ (NOM) | kdo? co? | Subject | uživatel | aplikace | | Genitiv (GEN) | koho? čeho? | Possession, "of", absence, 5+ count | uživatele | aplikace | | Dativ (DAT) | komu? čemu? | Indirect object, "to" | uživateli | aplikaci | | Akuzativ (ACC) | koho? co? | Direct object | uživatele (animate=GEN) / soubor (inanimate=NOM) | aplikaci | | Vokativ (VOC) | — | Direct address — ACTIVE in Czech | uživateli! | aplikace! | | Lokál (LOK) | o kom? čem? | Location (always w/ prep) | o uživateli | o aplikaci | | Instrumentál (INS) | s kým? čím? | "With", means | s uživatelem | s aplikací |

Critical: animate masculine accusative = genitive form. vidím uživatele, NOT vidím uživatel.

Vocative usage — Czech ACTIVELY uses vocative for direct address (unlike Slovak/Russian where it's archaic/merged). When a Czech product UI greets the user by name or addresses a role:

| ✗ Wrong (nominative) | ✓ Correct (vocative) | |----------------------|----------------------| | Ahoj, Petr! | Ahoj, Petře! | | Vážený uživatel! | Vážený uživateli! | | Děkujeme, Pavel! | Děkujeme, Pavle! | | Karel! | Karle! |

Common vocative endings: m.anim. -e/-i (Petr → Petře, Karel → Karle, učitel → učiteli), f. usually = nominative (Marie → Marie), n. = nominative.

5. Preposition + governed case (severity 2.5)

| Preposition | Case | Example | |-------------|------|---------| | v / ve (in) | LOK (location) | v systému | | do (into) | GEN | do systému | | na (on/onto) | LOK / ACC | na obrazovce / na obrazovku | | s / se (with) | INS | s uživatelem | | bez (without) | GEN | bez chyb | | pro (for) | ACC | pro uživatele | | od (from) | GEN | od uživatele | | k / ke (to/toward) | DAT | k uživateli | | o (about) | LOK | o uživateli | | po (after) | LOK | po přihlášení | | před (before) | INS / ACC | před uložením | | za (per / behind) | ACC / INS | za soubor / za stolem | | u (at, by) | GEN | u uživatele | | z / ze (from) | GEN | z aplikace |

"per" in Czech: use za + ACC for rate (za soubor), na + ACC for distribution (na uživatele), denně for "per day". Never per soubor (English calque).

6. ICU plurals — one / few / other (1 / 2-4 / 0+5+ with 11-14 going to other) (severity 2.5)

{count, plural,
  one {# soubor}
  few {# soubory}
  other {# souborů}
}

CLDR plural category boundaries:

| Category | Rule | Examples | Noun form | |----------|------|----------|-----------| | one | n = 1 | 1 | NOM singular (soubor) | | few | n ∈ {2, 3, 4} | 2, 3, 4 | NOM plural (soubory) | | other | n = 0 OR n ≥ 5 OR fractions | 0, 5-100, 1.5, 11, 12, 13, 14 | GEN plural (souborů) |

Note vs other Slavic: Czech is simpler than Russian/Ukrainian/Croatian/Slovak here — only one / few / other (3 categories), no many category. 11-14 fall into other, NOT few.

7. Numeral-noun agreement (severity 2.0)

| Count | Pattern | Example | |-------|---------|---------| | 1 | NOM sg | 1 soubor | | 2, 3, 4 | NOM pl | 2 soubory, 3 systémy | | 5+ | GEN pl | 5 souborů, 10 uživatelů | | 11-14 | GEN pl (same as other 5+) | 11 souborů, 12 systémů | | 21 | NOM sg (back to "one") | 21 souborů — WAIT, actually Czech is different from Russian here | | 22-24 | varies by interpretation — commonly NOM pl when "21 = 1+20" interpretation isn't applied | (Czech generally treats 21+ as other = gen.pl. in modern usage) |

Modern Czech tends to use GEN pl for everything 5+ including 21, 22, etc., though strict prescriptive grammar sometimes calls for NOM sg with 21, 22 etc. For UI, GEN pl is the safer default for 5+.

8. Three-gender + masculine animate/inanimate (severity 2.0)

Czech distinguishes masculine animate vs masculine inanimate (matters for accusative case):

| Gender | Example | Adjective NOM sg. | |--------|---------|-------------------| | Masc. animate (humans, named animals) | uživatel, programátor | nový uživatel | | Masc. inanimate (objects, abstracts) | soubor, systém, počítač | nový soubor | | Feminine (-a ending mostly) | aplikace, složka, databáze | nová aplikace | | Neuter (-o/-e/-í ending) | nastavení, okno, zařízení | nové nastavení |

Wrong gender adjective is auto-fail: nová soubor ✗, nový aplikace ✗, nová nastavení ✗.

9. Past-tense gender agreement (severity 1.5)

| Subject | L-participle | Example | |---------|--------------|---------| | m. sg. | -l | on pracoval | | f. sg. | -la | ona pracovala | | n. sg. | -lo | ono pracovalo | | m. anim. pl. | -li | oni pracovali | | f. pl. / m. inan. pl. | -ly | ony pracovaly / soubory se uložily | | n. pl. | -la | okna se otevřela |

10. Clitic second-position rule (severity 2.0)

Czech clitics (se, si, by, bych, bys, jsem, jsi, mi, ti, mu, jí, ho, tě, etc.) MUST go in the second position of their clause (Wackernagel's law), same as other Slavic languages.

| ✗ Wrong | ✓ Correct | |---------|-----------| | Se mi to nelíbí | To se mi nelíbí | | Soubor se mu zobrazuje | Soubor se mu zobrazuje ✓ — wait, this is correct because se mu cluster is in position 2. The issue would be: Soubor mu se zobrazuje ✗ → Soubor se mu zobrazuje ✓ (clitic order: refl. se after AUX, before DAT) — actually Czech clitic order is: AUX → DAT → ACC → SE. So se mu is wrong; correct is mu se. Let me revise: | | Soubor se mu zobrazuje (if mu comes first lexically) | Actually Soubor mu se zobrazuje ← but in Czech se typically comes after dative? Let me use a clear example. |

Clitic cluster order in Czech:

1. AUX (jsem / jsi / je / jsme / jste / jsou / bych / bys / by / bychom / byste)
2. SE / SI (reflexive)
3. DAT (mi / ti / mu / nám / vám / jim)
4. ACC (mě / tě / ho / nás / vás / je)

Example: Já bych se mu byl zeptal. (AUX bych — SE se — DAT mu — past). For UI status messages this complex cluster is rare; the main rule is: se / si stays in 2nd position of the clause.

11. Verb aspect — perfective vs imperfective (severity 2.0)

Standard UI verb aspect pairs:

| Imperfective (process, ongoing) | Perfective (single completed event) | English | |--------------------------------|--------------------------------------|---------| | ukládat | uložit | save | | mazat | smazat | delete | | nahrávat | nahrát | upload / record | | stahovat | stáhnout | download | | otevírat | otevřít | open | | zavírat | zavřít | close | | vytvářet | vytvořit | create | | upravovat | upravit | edit | | měnit | změnit | change | | posílat | poslat | send | | psát | napsat | write | | číst | přečíst | read | | vybírat | vybrat | choose / select | | překládat | přeložit | translate | | přihlašovat se | přihlásit se | log in |

UI patterns by aspect:

• Buttons (single action) → perfective infinitive: Uložit, Smazat, Poslat, Vybrat. The Czech UI convention is INFINITIVE (not imperative).
• Ongoing status → imperfective verbal noun (Ukládání…, Načítání…) or Probíhá + verbal noun.
• Completed → perfective neuter participle (Uloženo, Načteno, Přeloženo).

12. Verb-construction integrity — no stacked finite verbs (severity 2.0)

English -ing (gerund as adverbial) MUST be rendered with přechodník (Czech verbal adverb in -ouc/-íc/-e) OR restructure with při + verbal noun. Note: the přechodník is somewhat literary/archaic in modern Czech — při + verbal noun is more common in product copy.

| ✗ Stacked finite | ✓ Restructured | English | |------------------|-----------------|---------| | Strávil jsem 6 let stavěl jsem firmu | Strávil jsem 6 let stavbou firmy OR Strávil jsem 6 let při budování firmy | I spent 6 years building the business | | Pracoval jsem dokud jsem psal zprávu | Pracoval jsem při psaní zprávy | I worked while writing the report |

---

Pronouns and Possessives

Personal pronouns

| English | Czech | Notes | |---------|-------|-------| | I | já | | | you (sg. informal) | ty | | | you (sg./pl. formal — capitalize) | Vy | Always capitalized in direct address | | you (pl. informal) | vy | lowercase when truly plural informal | | he | on | | | she | ona | | | it | ono | | | we | my | | | they (m. anim.) | oni | | | they (m. inan. / f.) | ony | | | they (n.) | ona | |

Possessive pronouns

| Person | m. sg. | f. sg. | n. sg. | |--------|--------|--------|--------| | můj (my) | můj | moje / má | moje / mé | | tvůj (your sg.) | tvůj | tvoje / tvá | tvoje / tvé | | Váš (your formal — capitalize) | Váš | Vaše / Vaše | Vaše | | jeho (his — invariable) | jeho | jeho | jeho | | její (her) | její | její | její | | svůj (reflexive — own) | svůj | svoje / svá | svoje / své | | náš (our) | náš | naše | naše | | jejich (their — invariable) | jejich | jejich | jejich |

Reflexive svůj is required when possessor = subject of same clause.

---

UI Conventions

Buttons — INFINITIVE (the Czech UI convention)

Czech platform UIs (Windows CZ, Chrome CZ, macOS CZ) use infinitive for buttons — NOT imperative. This is a deliberate convention choice and matches what users see in their OS.

| English | ✓ Infinitive (button) | (Vy-imperative — for instruction prose) | |---------|------------------------|------------------------------------------| | Save | Uložit | Uložte | | Cancel | Zrušit / Storno | Zrušte | | Delete | Smazat / Odstranit | Smažte / Odstraňte | | Send | Odeslat | Odešlete | | Edit | Upravit | Upravte | | Search | Hledat | Hledejte | | Confirm | Potvrdit | Potvrďte | | Continue | Pokračovat | Pokračujte | | Submit | Odeslat | Odešlete | | Sign in / Log in | Přihlásit se | Přihlaste se | | Sign out | Odhlásit se | Odhlaste se | | Sign up | Zaregistrovat se | Zaregistrujte se | | Next | Další / Pokračovat | (same) | | Back | Zpět | (same) | | Done | Hotovo / Dokončeno | (same) | | OK | OK / Souhlasím | (same) | | Close | Zavřít | Zavřete | | Upload | Nahrát | Nahrajte | | Download | Stáhnout | Stáhněte | | Refresh | Aktualizovat / Obnovit | Aktualizujte | | Settings | Nastavení | (same) | | Apply | Použít | Použijte | | Reset | Resetovat / Obnovit původní | — | | Select all | Vybrat vše | Vyberte vše | | Deselect all | Odznačit vše / Zrušit vše | — | | Add more | **Přidat dal

…

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: i18n-agent
• Source: i18n-agent/i18nstack
• License: MIT
• Homepage: https://i18nagent.ai

Install and usage instructions live in the source repository linked above.