Spelling of Foreign and Loan Words

Czech spelling is famously phonemic — you write roughly what you say — and it applies that principle to borrowed words too. Over time Czech "czechizes" a loanword: it swaps foreign letters for native ones that match the pronunciation, drops silent letters, and simplifies doubled consonants. The result is that thousands of internationalisms look reassuringly familiar but are spelled the Czech way. The trap for English speakers is obvious: you already know these words, so you write them the English way — philosophy, discussion, address — and get them wrong. This page shows the regular substitutions, then the awkward cases where an older and a newer spelling both survive.

The regular substitutions

Most borrowings follow a predictable set of letter swaps that bring the spelling in line with how Czech actually pronounces the word.

The -tion → -ce family

English -tion and -sion nouns are extremely common and land in Czech as -ce (feminine, declined like růže). Once you internalize this you can convert on the fly.

The i / y question in loanwords

Native Czech words obey the hard/soft consonant rules and the vyjmenovaná slova lists for when to write i versus y. Loanwords are simpler: after the historically "neutral" consonants they generally keep i, following the source form, because the y-spelling rules were about native roots. So you write disk, kino, pilot, gymnázium, fyzika — the y in fyzika and gymnázium is inherited from Greek ph-/gy-, not from any vyjmenovaná slova rule.

-ismus, not -ism

English abstract nouns in -ism correspond to Czech -ismus (or the more phonetic -izmus), a masculine inanimate noun. Do not clip it to -ism.

Both -ismus and -izmus are permitted; -ismus is the traditional, stylistically neutral form and is what you will see most in careful writing, while -izmus is the more phonetic variant. The same s/z wobble runs through a whole set of loanwords, discussed below.

The kh / ch decision and other digraphs

Foreign kh (as in transliterated names) is usually rendered ch in Czech, since ch is the native → Chartúm, *khan → chán. Foreign sch [ʃ] becomes š (schnitzel → šnicl), and sh [ʃ] also becomes š (shampoo → šampon). English ck collapses to k (hockey → hokej, jockey → žokej).

Where two spellings coexist

Here is the genuinely messy part, and there is no clean rule — you simply have to know that certain common loanwords have two accepted spellings, an older s-form and a newer, more phonetic z-form (or an s/z pair, or a th/t pair). A 1990s codification blessed the phonetic variants, so both now appear in print.

The trend is clear: the phonetic z-forms have won in everyday use. Almost nobody writes filosofie or diskuse in a text message; filozofie, diskuze, and kurz dominate. But the s-forms remain correct and are still felt as slightly more formal or old-fashioned. Reference works treat the s-form as the neutral base for some of these and the z-form for others, which is why even Czechs check.

The gradual czechization of recent loans

The newest borrowings — mostly from English — are caught mid-adaptation. You will see the raw English spelling and a czechized spelling competing, and over a decade or two the Czech form tends to win. Watch this happen in real time:

Common Mistakes

Key Takeaways

• Czech czechizes loanwords toward its phonemic spelling: c→k, qu→kv, ph→f, th→t, -tion→-ce, and doubled consonants → single.
• English -ism → Czech -ismus (or phonetic -izmus); kh → ch; sch/sh → š.
• A set of common loans have two accepted spellings (filozofie/filosofie, kurz/kurs, diskuze/diskuse) — the phonetic z-form now dominates everyday use.
• Recent English loans are mid-adaptation (manažer, byznys, víkend, displej); the czechized form usually wins over time.
• The English-speaker trap is keeping the English spelling — write the Czech form, and when unsure about single vs double letters, write single.