Second-person singular imperative

To form the imperative, start with the 3rd-person plural present tense (e.g., oni nesou, oni dělají) and drop the final -ou or -í.

1. Zero ending (-∅)
If dropping -ou or -í leaves a single consonant, add nothing.

• nesou → nes! (carry!)
• platí → plať! (pay! - note the t, d, n mutate to ť, ď, ň)
• koupí → kup! (buy! - long root vowels usually shorten)

Shortcut for -ovat verbs: Verbs ending in -ovat (e.g., pracovat) always form their imperative with -uj! (pracují → pracuj!).

2. The -i ending
If dropping -ou or -í leaves a consonant cluster, add -i for easier pronunciation.

• čtou → čti! (read!)
• tisknou → tiskni! (press/print!)

Note: Verbs ending in -stit often take a zero ending and mutate (e.g., pustit strictly becomes pusť!). For some, like čistit, both the mutated zero ending (čisť!) and the -i ending (čisti!) are valid.

3. The -ej / -ěj ending
For verbs ending in -at in the infinitive (like dělat, čekat) where the 3rd-person plural ends in -ají, drop the final -í and change the a to e. For verbs where the 3rd-person plural ends in -ejí or -ějí, simply drop the final -í.

• dělají → drop -í (dělaj) → change a to e → dělej! (do/make!)
• rozumějí → drop -í → rozuměj! (understand!)

Forming Plural and 'Let's' Commands:
For verbs with a zero or -ej ending, simply add -te for plural/formal commands (e.g., kup → kupte!) or -me for 'let's' commands (e.g., kup → kupme!). However, for verbs with the -i ending, drop the -i and add -ěte/-ete or -ěme/-eme (e.g., čti → čtěte! / čtěme!, tiskni → tiskněte! / tiskněme!).

Reflexive Verbs:
If a verb uses the reflexive pronouns se or si, the pronoun typically follows the imperative form.

• posadit se → posaď se! (sit down!)
• koupit si → kup si! (buy for yourself!)

Irregular Imperatives:
Some of the most common verbs have irregular imperative forms that must be memorized:

• být → buď! (be!)
• mít → měj! (have!)
• jít → jdi! / pojď! (go! / come!)
• jíst → jez! (eat!)
• stát → stůj! (stand/stop!)
• pomoci → pomoz! (help!)
• vědět → věz! (know! - highly formal or archaic)

The Role of Aspect:
Use perfective verbs for affirmative, one-off requests (Zavři! = Close it!). Use imperfective verbs for negative prohibitions (Nezavírej! = Don't close it!).
Exception: Negative perfective verbs are used for accidental warnings (e.g., Nezapomeň! = Don't forget!, Neupadni! = Don't fall!).

Note: Czech commands are not inherently rude. Native speakers soften them using aspect choices, diminutives (chvilku), or particles (no tak, jen), rather than always relying on the word prosím (please).