The Glottal Stop Before Initial Vowels

There is a tiny sound in Czech that isn't written with any letter, yet it shapes how the language is heard: the glottal stop, the brief catch in the throat you make in the middle of English "uh-oh." Czech inserts this little stop before a vowel that begins a word — and, crucially, before a vowel that begins a morpheme inside a word, right after a prefix. The effect is that words and their parts stay audibly separate: Czech does not glide smoothly from one word into the next the way English and French do. Get this, and your Czech instantly sounds less foreign; miss it, and you blur word boundaries in a way that marks you out at once.

Throughout, the glottal stop is shown in the prose as the IPA symbol in square brackets. The example sentences themselves are ordinary, fully spelled Czech — the catch in the throat is something you do, not something you write.

What the glottal stop is

The glottal stop, written [ʔ] in IPA, is made by briefly closing and releasing the vocal cords — the same gesture as the catch in "uh-oh" or the way a cockney speaker says "bo'le" for "bottle." It is not a Czech letter and never appears in spelling. It is a boundary marker: Czech reaches for it whenever a vowel would otherwise have to start "from nothing," to give that vowel a clean, hard onset.

English does the opposite. English links across boundaries: "an apple" comes out as "a-napple," "far away" as "fa-raway." Czech refuses this linking before initial vowels. Where English glides, Czech inserts a stop and keeps the pieces apart.

Before a word that starts with a vowel

Whenever a word begins with a vowel and follows another word, Czech puts a glottal stop in front of that vowel. The two words do not run together.

Take v okně "in the window." English ears expect "vokně," all blended. But a Czech speaker says it as v + [ʔ] + okně — the preposition is detached, the vowel of okně gets its own hard start. Likewise za oknem "behind the window" is za + [ʔ] + oknem, not a smooth "zaoknem."

This is most noticeable after the one-consonant prepositions v, k, s, z, u, o, exactly because English would link them so hard. v autě "in the car," o obědě "about lunch," k oknu "towards the window" — each has a clear [ʔ] before the vowel.

At the prefix–vowel boundary inside a word

This is the part that catches learners off guard: the glottal stop appears inside words too, right after a prefix, when the root begins with a vowel. The prefix and the root are kept audibly distinct.

• neexistuje "(it) doesn't exist" = ne
  • [ʔ] + existuje. Not a long blurred "neeg-zistuje"; the two e's are separated by the stop: ne-[ʔ]-existuje.
• po obědě and the prefixed poobědvat "to have lunch" = po
  • [ʔ] + the vowel.
• neúplný "incomplete" = ne
  • [ʔ] + úplný; the e and the long ú do not merge.
• přeučit "to re-teach / retrain" = pře
  • [ʔ] + učit.

This is the same hiatus-breaking job: when a vowel-final prefix meets a vowel-initial root, the glottal stop steps in so the seam between the two morphemes stays clear.

Why "v okně" doesn't blend

It's worth being explicit about the contrast, because it is the single hardest habit for English speakers to break. In English, "in October" becomes "i-noctober"; the n of "in" jumps onto the next syllable. A Czech speaker hearing "vokně" as one smooth stream would find it slurred, even hard to parse — because the [ʔ] is part of how the boundary is recognised. Czech keeps the preposition as its own little unit and gives okně a fresh, hard start. The result is a clipped, separated rhythm rather than English's connected legato.

This separation also protects meaning. dvě auta "two cars" is dvě + [ʔ] + auta — keep the words apart and it's unmistakable. Run them together and the boundary blurs. (Note the agreement here: it really is dvě auta, neuter, not dva auta — auto is neuter.)

Interaction with voicing assimilation

Here is the subtle bit, and it links straight to the voicing assimilation page. Normally, a preposition like v or z assimilates its voicing to whatever follows. Before a voiceless consonant, voiced v devoices: v Praze is fine and voiced, but v kapse "in the pocket" has v pronounced like [f].

So what happens before a vowel? A vowel is voiced, and the glottal stop sits between the preposition and that vowel. The glottal stop itself is voiceless (it's just a closure of the cords), which is why, across this boundary, the assimilation does not voice things up the way a following vowel otherwise might. In careful speech, v okně keeps a clean separated onset rather than gliding into a single voiced stream. The practical upshot for a learner: don't expect the smooth voiced liaison English would give you here — the glottal stop blocks it and holds the boundary.

When the stop is weaker

The glottal stop is strongest in careful, deliberate, or emphatic speech and at the start of an utterance. In fast, casual conversation it can soften — Czechs don't hammer it on every single vowel, and over-doing it sounds stiff. But the default, and the safe target for a learner, is to produce it clearly at word and prefix boundaries. You will never sound wrong for separating the words; you can sound foreign for linking them English-style.

The one place it's essentially obligatory and most audible is at the very start of an utterance before an initial vowel, and after the small prepositions. Aim for it there first.

How to practise it

Say English "uh-oh" slowly and feel the catch between the syllables. That catch is the glottal stop. Now take v okně and put exactly that catch before okně: "v — [ʔ]okně." Do the same inside words: ne — [ʔ]existuje, ne — [ʔ]úplný. Exaggerate the separation at first; the goal is to override the deep English instinct to link. Once the separation is automatic, you can let it relax to a natural level.

Common Mistakes

These pairs share the same spelling; the error is phonetic, marked in the translation.

Key Takeaways

• Czech inserts a glottal stop [ʔ] — a brief catch in the throat — before a vowel that starts a word (v okně, za oknem) or a morpheme after a prefix (neexistuje, neúplný, přeučit).
• It is a separator: where English links words smoothly ("a-napple"), Czech keeps them apart with a hard onset.
• It blocks English-style liaison and interacts with voicing assimilation by holding the boundary rather than letting it blend.
• It is strongest in careful and utterance-initial speech; over-separate while learning, then relax.
• The English-speaker pitfall is linking ("vokně," "nogzistuje"); the fix is to plant the "uh-oh" catch before every initial vowel.