Nárok na osvobození musí držitel psa ohlásit.

Czech word order is much more flexible than English word order. The sentence starts with Nárok na osvobození to put that information first, probably because it is the topic or focus in this administrative/legal context.

A more neutral learner-friendly order would be:

Držitel psa musí nárok na osvobození ohlásit.

Both mean the same thing. The original just sounds more formal and text-like.

The subject is držitel psa.

That means the holder/owner of the dog. This is the person who must report something.

Even though it comes later in the sentence, it is still the subject.

Nárok is the direct object of ohlásit, so it is in the accusative.

However, nárok is a masculine inanimate noun, and in the singular its nominative and accusative forms are the same:

• nominative: nárok
• accusative: nárok

So the form does not change, even though the function does.

Because nárok normally takes the preposition na when it means claim to / entitlement to / right to something.

So:

• nárok na něco = entitlement/claim to something

Here:

• nárok na osvobození = entitlement to exemption

This is just the standard pattern you need to learn with the noun nárok.

After na in this meaning, Czech uses the accusative.

So na osvobození is accusative.

A small complication: osvobození is a neuter noun, and its nominative and accusative singular are identical, so again you do not see a visible ending change. But grammatically, it is accusative here.

Because držitel is followed by the genitive to show what someone is the holder/owner of.

So:

• držitel psa = holder/owner of a dog

Here psa is genitive singular of pes.

This is a very common Czech pattern:

• majitel domu = owner of a house
• řidič autobusu = driver of a bus
• držitel psa = holder/owner of a dog

Not always exactly, but they can overlap.

• majitel = owner
• držitel = holder, possessor, registered keeper, legal holder

In official or legal language, držitel psa can be used where English would often simply say dog owner. It may sound slightly more formal or administrative than majitel psa.

Because it is the infinitive used with the modal verb musí.

In Czech, modal verbs such as muset, moci, chtít are followed by an infinitive:

• musí ohlásit = must report

The infinitive often comes later or at the end of the clause, especially in formal writing, though Czech allows some variation.

Because ohlásit is perfective, while hlásit is imperfective.

• ohlásit = to report, to declare, as a completed act
• hlásit = to report, announce, or declare in a more ongoing/repeated/general sense

In an administrative sentence about an obligation to submit or declare something, perfective ohlásit is very natural, because the idea is that the person must complete that reporting action.

Yes. That would be a very normal version and probably easier for a learner to parse.

The original:

Nárok na osvobození musí držitel psa ohlásit.

The more straightforward order:

Držitel psa musí nárok na osvobození ohlásit.

The difference is mainly one of emphasis and style, not basic meaning.

Yes. Several things make it sound official or administrative:

• držitel instead of a more everyday word
• nárok na osvobození as a legal/bureaucratic phrase
• the marked word order
• ohlásit in a formal reporting sense

This is the kind of sentence you might see in regulations, forms, municipal rules, or legal instructions.

Because Czech has no articles.

English needs words like the and a/an, but Czech does not. So a phrase like držitel psa can mean:

• the dog owner
• a dog owner
• the holder of the dog

The exact interpretation comes from context, not from an article.

Yes, and that is a very good idea.

Treat nárok na osvobození as a fixed expression meaning:

• entitlement to exemption
• claim to exemption
• right to exemption

This will help you understand the sentence more easily, because the whole phrase functions together as the object of ohlásit.