High-frequency verbs that don't follow standard patterns. Their irregularity often preserves ancient forms or results from sound changes.
How to Identify
Memorize these individually: být (be), mít (have), jíst (eat), vědět (know), chtít (want), moct (can), jít (go).
Each verb has its own stem changes. 'Být' has completely suppletive forms (jsem, jsi, je—nothing like 'být'). 'Jíst' becomes 'jím, jíš, jí'.
Why Endings Encode the Subject
Irregular verbs are irregular BECAUSE they're used so frequently. High-frequency words resist regularization—speakers learn them by heart and preserve archaic forms. English 'be/am/is/are/was/were' shows the same phenomenon.
Example Verbs6
Present Tense
Past Tense (with gender)
(suppletive)Completely irregular. Present tense forms (jsem, jsi, je...) have no relation to the infinitive 'být'. This is called suppletion—the same phenomenon as English be/am/is/are.
Present Tense
Past Tense (with gender)
má-The stem shows vowel lengthening: mít → má-. The long 'á' appears in all present tense forms.
Present Tense
Past Tense (with gender)
j-/jed-Two stems: present uses j- (jím), past uses jed- (jedl). This alternation is a remnant of ancient Indo-European ablaut patterns.
Present Tense
Past Tense (with gender)
ví-/věd-Present stem ví- (vím), past stem věd- (věděl). Another case of stem alternation.
Present Tense
Past Tense (with gender)
chc-/chtěj-Stem alternates: chc- in singular (chci), chtěj- in plural (chtějí). First person is especially irregular.
Present Tense
Past Tense (with gender)
jd-Present stem jd- (jdu). Motion verbs in Czech are notoriously complex, with different verbs for 'go by foot' vs 'go by vehicle'.