Zamíchej balíček, prosím.

Zamíchej is the singular informal imperative form of the verb zamíchat.

So it means shuffle! / mix! when speaking to one person you address as ty.

Related forms:

• zamíchat = infinitive, to shuffle / to mix
• zamíchej! = command to one person
• zamíchejte! = command to more than one person, or to one person formally

This is a very common Czech aspect question.

• zamíchat is perfective
• míchat is imperfective

In a command like this, Czech often uses the perfective imperative when you want someone to do one complete action:

• Zamíchej balíček. = Shuffle the deck.
  → do it once, as a completed action

By contrast:

• Míchej. = Keep mixing / be mixing.
  → focuses more on the process or repeated action

So zamíchej sounds natural for a single request such as shuffling a deck of cards.

Balíček is the direct object of the sentence, so it is in the accusative case.

However, balíček is a masculine inanimate noun, and for many masculine inanimate nouns, the accusative singular looks the same as the nominative singular.

So:

• nominative: balíček
• accusative: balíček

That is why the form does not visibly change here.

Literally, balíček often means small package, packet, or bundle.

But in context, it can also mean a pack/deck, especially a deck of cards. In a sentence with zamíchej (shuffle), the intended meaning is naturally something like the deck / the pack of cards.

So even though the core meaning of balíček is broader, the verb makes the card-related meaning clear.

Prosím means please, and Czech word order is fairly flexible.

So all of these are possible:

• Zamíchej balíček, prosím.
• Prosím, zamíchej balíček.
• Zamíchej, prosím, balíček.

The version with prosím at the end is very natural and common. It sounds polite without changing the basic command structure.

It is informal, because zamíchej is the imperative used with ty.

If you wanted to say the same thing:

• to several people, or
• to one person formally,

you would say:

• Zamíchejte balíček, prosím.

So:

• zamíchej = informal singular
• zamíchejte = formal singular or plural

In Czech, the subject pronoun is often omitted because the verb form already shows who is being addressed.

Here, zamíchej already tells you it means you (singular, informal) shuffle!

So Czech usually does not need:

• Ty zamíchej balíček.

That version is possible, but it would add emphasis, contrast, or impatience. The neutral everyday version is simply:

• Zamíchej balíček, prosím.

A simple pronunciation guide:

• zamíchej ≈ ZA-mee-khej
• balíček ≈ ba-LEE-chek
• prosím ≈ PRO-seem

Useful pronunciation notes:

• Czech stress is usually on the first syllable of each word.
• ch is one sound, like the ch in German Bach or Scottish loch, not like English ch in chair.
• í is a long ee sound.
• č sounds like ch in chair.

Yes. Some natural alternatives are:

• Zamíchej karty, prosím. = Shuffle the cards, please.
• Prosím, zamíchej balíček.
• Zamíchejte balíček, prosím. = formal / plural

If the context is clearly a card game, Czech speakers may also choose wording with karty (cards) instead of balíček. But your sentence is understandable and natural in the right context.

Yes, normally prosím is separated by a comma when used as a polite parenthetical word like please.

So the standard punctuation is:

• Zamíchej balíček, prosím.

Similarly:

• Prosím, zamíchej balíček.
• Zamíchej, prosím, balíček.

The commas show that prosím is not part of the core grammar of the sentence, but a polite addition.