Držte dveře, prosím.

Držte is the imperative form used for:

• more than one person: Hold the door, you all
• one person formally/politely: Hold the door, please

By contrast, drž is the imperative for one person informally.

So:

• Drž dveře, prosím. = said to one friend, child, someone you address with ty
• Držte dveře, prosím. = said to several people, or to one person politely with vy

It can mean either:

1. one person formally
2. more than one person

Czech uses the same verb form for both. You can usually tell from the situation.

This is very common in Czech:

• Pojďte dál. = Come in.
  
  • either to one person politely
  • or to several people

In Czech, dveře is a plural-only noun. It refers to a door in general, but grammatically it behaves like a plural word.

So even for one door, Czech says:

• Ty dveře jsou otevřené. = The door is open.
• Zavři dveře. = Close the door.

This is similar to how English has nouns like scissors or pants, which are grammatically plural even when they refer to one object.

Here dveře is in the accusative case, because it is the direct object of the verb držte.

You are holding what?
→ dveře

With dveře, the accusative plural looks the same as the nominative plural:

• Dveře jsou těžké. = The door is heavy. / The doors are heavy.
• Držte dveře. = Hold the door.

So the form does not change here, even though the case changes.

Czech usually does not need subject pronouns if the verb already shows who is being addressed.

The ending -te in držte already tells you this is:

• plural you
• or formal you

So Vy držte dveře, prosím. is possible, but usually unnecessary unless you want extra emphasis or contrast.

Prosím makes the sentence more polite, like please in English.

So:

• Držte dveře. = Hold the door.
• Držte dveře, prosím. = Hold the door, please.

Its position is fairly flexible. You may also hear:

• Prosím, držte dveře.
• Držte, prosím, dveře.

All are natural, though Držte dveře, prosím. is very straightforward and common.

It is understandable and correct, but in many everyday situations Czech speakers may prefer podržte dveře, prosím.

The difference is about aspect:

• držet = to hold, to keep holding
• podržet = to hold for a moment, to hold briefly

So:

• Držte dveře. can sound like keep holding the door
• Podržte dveře. often sounds more like hold the door for a moment

If you mean the everyday polite action of keeping the door open for someone, Podržte dveře, prosím. is often especially natural.

A rough pronunciation guide is:

• držte ≈ drzh-te
• dveře ≈ dveh-rzhe

A few helpful points:

• Czech stress is usually on the first syllable: DRŽ-te DVE-ře
• ž sounds like the s in measure
• ř is a special Czech sound, something like a mix of r and zh. Learners often find it difficult, and that is normal.

You do not need perfect ř right away to be understood.

The infinitive is držet, meaning to hold.

A few useful forms are:

• držet = infinitive
• držím = I hold / I am holding
• držíš = you hold (informal singular)
• drží = he/she/it holds
• držte = hold! (plural/formal imperative)

So in this sentence, držte is the command form built from držet.

You would say:

• Drž dveře, prosím.

That uses the singular informal imperative drž.

So the contrast is:

• Drž dveře, prosím. = to one person informally
• Držte dveře, prosím. = to one person formally or to several people

This is one of the most important distinctions in Czech everyday speech.