Znám autora.

Because autora is the accusative singular form of autor.

In Znám autora, autora is the direct object of the verb znát, so Czech puts it in the accusative case.

A key point:

• autor is a masculine animate noun, because it refers to a person.
• In the singular, masculine animate nouns often have:
  • nominative: autor
  • accusative: autora

So:

• Autor píše. = the author is writing
• Znám autora. = I know the author / an author

Znám is the 1st person singular present tense of the verb znát.

So it means:

• I know
• I am familiar with

The infinitive is znát.

A few present-tense forms:

• znám = I know
• znáš = you know
• zná = he/she/it knows
• známe = we know
• znáte = you know
• znají = they know

Because Czech often omits subject pronouns when they are clear from the verb form.

The ending in znám already tells you the subject is I.

So:

• Znám autora. = normal, natural
• Já znám autora. = also correct, but já adds emphasis or contrast

For example:

• Já znám autora, ale ty ne. = I know the author, but you do not.

This is a very common question.

Use znát for being familiar with a person, place, thing, song, book, etc.

Use vědět for knowing a fact or piece of information.

So:

• Znám autora. = I know the author
• Znám Prahu. = I know Prague
• Vím, kde bydlí. = I know where he lives
• Vím odpověď. = I know the answer

A simple rule:

• znát = know someone/something
• vědět = know that..., know where..., know a fact

Usually, yes, or at least it suggests some kind of familiarity.

With a person, znát often means:

• to know someone personally
• to be acquainted with someone
• to be familiar with someone

But the exact level of familiarity depends on context. It does not always have to mean close friendship.

No. Czech word order is fairly flexible because case endings show the grammatical role.

The neutral order is:

• Znám autora.

But you could also hear:

• Autora znám.

Both are grammatical. The difference is mainly in emphasis or information structure.

Very roughly:

• Znám autora. = neutral statement
• Autora znám. = the author, I know him

So the case ending -a helps show that autora is the object even if the order changes.

Because Czech has no articles.

So autor or autora can mean:

• an author
• the author

The exact meaning depends on context.

That means Znám autora could mean:

• I know the author
• I know an author

In real use, context tells you which one is meant.

A simple pronunciation guide is:

• Znám ≈ znaam
• autora ≈ ow-to-ra

A few useful points:

• á is a long vowel, so it is held longer than short a
• Czech stress normally falls on the first syllable of each word:
  • ZNÁM
  • AUtora
• In zn, both sounds are pronounced: z
  • n

So do not reduce it to something like a weak English unstressed vowel pattern; Czech pronunciation is usually clearer and more even.

The dictionary form is autor.

When you look up Czech nouns, you normally look for the nominative singular form, which is the basic form:

• autor = dictionary form
• autora = accusative singular here

So if you see autora in a sentence and want to check it in a dictionary, search for autor.

Yes, in other contexts znám can also be an adjective form meaning known in older or more literary usage, but in this sentence it is clearly a verb.

Why it is clearly a verb here:

• it is followed by a direct object: autora
• the sentence works as a complete clause: I know the author

So in Znám autora, you should understand znám as the verb I know.