PIN je v dopise.

Je is the 3rd person singular present form of být, which means to be. In this sentence, it means is.

So:

• PIN = the subject
• je = is
• v dopise = in the letter

Unlike in some languages, Czech normally does not leave out is in this kind of sentence.

Because the preposition v meaning in takes the locative case when it expresses location.

The basic dictionary form is dopis = letter.
After v, it changes to dopise.

So:

• dopis = nominative singular
• v dopise = locative singular, meaning in the letter

It is the locative singular.

In this sentence:

• PIN is in the nominative, because it is the subject.
• dopise is in the locative, because it follows v and shows location.

This is a very common pattern in Czech:

• v domě = in the house
• v autě = in the car
• v dopise = in the letter

It is singular.

Even though the ending -e may look unusual to an English speaker, here it does not mean plural. It is just the singular locative form of dopis.

For comparison:

• singular: v dopise = in the letter
• plural: v dopisech = in the letters

Czech does not have articles like English a and the.

So PIN je v dopise can mean:

• The PIN is in the letter
• A PIN is in a letter

In real use, the intended meaning usually comes from context. Very often, English translations add the because it sounds natural in English, even though Czech does not use a separate word for it.

Here v means in or inside.

It is a very common Czech preposition for location:

• v Praze = in Prague
• v domě = in the house
• v dopise = in the letter

So in this sentence, v tells you where the PIN is located.

Yes. Czech word order is more flexible than English word order.

The sentence PIN je v dopise is a neutral way to say it. But you could also say:

• V dopise je PIN.

That still means the same basic thing, but the emphasis changes a little.

A rough guide:

• PIN je v dopise. = neutral, starting with PIN
• V dopise je PIN. = emphasizes where it is, something like In the letter is the PIN or more naturally The PIN is in the letter

In Czech, word order often helps show what is already known and what is new or important.

Because PIN is an abbreviation, from Personal Identification Number.

In Czech, it is normally written as PIN, just like in English. In this sentence it stays in its basic form.

So:

• PIN je v dopise. = The PIN is in the letter.

A simple approximation for an English speaker is:

PIN ye v DO-pi-se

A few details:

• je sounds roughly like ye
• dopise has three syllables: do-pi-se
• Czech stress usually falls on the first syllable, so DO-pi-se

So the whole sentence is said smoothly as:

PIN je v dopise

Yes. Dopis is a masculine inanimate noun.

That matters because noun gender affects how words change in different cases. Here, its locative singular form is dopise.

So the learner-friendly pattern is:

• base form: dopis
• after v for location: v dopise