Irregular Past Participles

The regular Czech past is mechanical: drop -t from the infinitive, add -l — dělat → dělal, mluvit → mluvil. If every verb behaved that way, this page wouldn't exist. But a band of the most frequent verbs in the language form their l-participle on a different stem from their infinitive, and the change is not something you can derive from the infinitive's spelling. Worse for the learner, these are exactly the verbs you use every single day: go, eat, read, say, take, have, want, be able to. There is no way around learning them — but there is a logic to why they misbehave, and grouping them by that logic makes the memorisation far lighter.

The single most important habit this page tries to build: do not derive the past from the infinitive for these verbs. Číst does not give \čísl or *čítl; it gives četl. Treat the past stem as a fact about the verb, learned alongside it — and learn it *with its gender forms (šel / šla / šli), because that is where the irregularity is most visible and most error-prone.

Why these verbs are irregular

Almost all of these belong to the old consonant-stem and -st / -ci verb classes. Their infinitive endings (-st, -ct, -ci) are themselves the product of sound changes that fused a stem-final consonant with the infinitive -t centuries ago. The past participle preserves an older, "truer" stem that the infinitive has hidden. So nést "to carry" has the past stem nes- (giving nesl), and vést "to lead" has ved- (giving vedl) — the infinitive -st is a disguise over an underlying -s- or -d-. You don't need the historical detail, but it explains a recurring shape: the past participle often reveals a consonant the infinitive swallowed.

The core list to memorise

These ten verbs are the heart of the matter. Learn the masculine singular form (the bare -l form) plus, for the trickiest ones, the feminine and plural.

The gender/number endings themselves are completely regular — they are the same -a, -o, -i, -y, -a you add to any participle, covered on the agreement page. What's irregular is the stem you add them to.

The wild one: jít → šel / šla / šlo / šli

Jít "to go (on foot)" is the most irregular verb in the past tense, and it deserves its own warning. Its participle is suppletive — built from an entirely different root (šed-/šel-) that shares nothing recognisable with jít. English does the same thing with go → went, so the concept is familiar; you just have to learn a brand-new word.

Note the vowel difference you can hear: masculine šel has an -e- that the other forms drop (šla, šlo, šli, šly). That fleeting -e- is a remnant of the old stem and appears only in the masculine singular. The prefixed verbs of motion inherit the same pattern: přišel / přišla "came," odešel / odešla "left," našel / našla "found" — all built on the same -šel/-šla skeleton. (For the present tense of jít and jet, see irregular jít / jet.)

The disappearing vowel: nést → nesl, vést → vedl, plést → pletl

A whole class of "class-I" verbs in -st and -zt loses the vowel you might expect and lands a single consonant before the -l. The participle reveals the buried stem consonant:

The trap for English speakers is to "regularise" these into *nésl or *véstl. The real forms are short and consonant-final: nesl, vedl, pletl, rostl. Watch the contrast between nést → nesl (one s) and vést → vedl (the -st hides a -d-) — you cannot tell them apart from the infinitive alone.

The -ct / -ci verbs: moci → mohl, péct → pekl, říci → řekl

Verbs whose infinitive ends in -ct (older spelling -ci) hide a velar consonant — k, h, or č — that surfaces in the participle. The -ct ending is a fusion of that consonant with the old infinitive marker.

Moci → mohl keeps the h; péct → pekl and říci → řekl show k. These are high-frequency (you say mohl jsem "I could," řekl jsem "I said" constantly), so the payoff for learning them is immediate.

The vowel-shifters: vzít → vzal, jíst → jedl, číst → četl, mít → měl, chtít → chtěl

A final cluster changes the vowel between infinitive and participle in a way you cannot predict:

• vzít → vzal — the í becomes a. This is the perfective "to take"; its imperfective partner brát has the regular bral.
• jíst → jedl — a -d- appears and the long í shortens to e. (Contrast its near-twin číst → četl, with a -t-.)
• číst → četl — the long í of the infinitive becomes a short e, and a -t- surfaces. There is genuinely no way to guess this.
• mít → měl — the í becomes ě: měl, měla, měli. Extremely frequent ("had").
• chtít → chtěl — likewise í → ě: chtěl, chtěla, chtěli ("wanted").

A note on the auxiliary

None of this changes how the auxiliary behaves. In the 1st and 2nd person you still add the clitic jsem / jsi / jsme / jste in second position, exactly as on the past auxiliary page — the irregularity is purely in the participle stem. Šel jsem, řekl jsi, mohli jsme: the participle is irregular, the auxiliary attaches normally.

Common Mistakes

Key Takeaways

• A band of very frequent verbs build the l-participle on a different stem than the infinitive — do not derive the past from the infinitive for these.
• Suppletive: jít → šel / šla / šlo / šli (and prefixed přišel, odešel, našel); note the masculine-only -e- in šel.
• Disappearing-vowel class-I: nést → nesl, vést → vedl, plést → pletl, růst → rostl — short, consonant-final.
• -ct/-ci verbs hide a velar: moci → mohl, péct → pekl, říci → řekl, téci → tekl.
• Vowel-shifters: vzít → vzal, jíst → jedl, číst → četl, mít → měl, chtít → chtěl.
• The gender/number endings stay regular; only the stem is irregular. Learn each verb with its šel / šla forms.