Prije ovjere potpisa tumač čita privatnu ispravu.

Because prije meaning before normally requires the genitive case in Croatian when it is used as a preposition.

So:

• ovjera → ovjere in the genitive singular
• potpis → potpisa in the genitive singular

That is why you get:

• prije ovjere potpisa = before the certification of the signature

The structure is:

• prije
  • genitive
• ovjera potpisa = certification of the signature

So both nouns are changing because they are part of a genitive phrase.

Ovjera means certification, verification, or notarization, depending on context.
Potpisa is of the signature.

So ovjera potpisa is literally:

• certification of the signature

In legal or administrative contexts, this often refers to an official confirmation that a signature is genuine or properly witnessed.

Because potpis depends on ovjera.

This is a very common Croatian noun + noun pattern:

• ovjera potpisa = certification of the signature
• kopija dokumenta = copy of the document
• tekst zakona = text of the law

The second noun often goes into the genitive to show a relationship similar to English of.

So:

• ovjera = certification
• potpisa = of the signature

In general Croatian, tumač can mean interpreter or, in some official/legal contexts, a sworn translator/interpreter.

In a sentence like this, especially with legal vocabulary such as ovjera and isprava, tumač probably refers to an official language professional, often someone authorized to read or interpret a document for a person before a formal act takes place.

So the exact English word depends on the context, but interpreter is often the safest basic understanding for a learner.

Čita is the present tense, third person singular, from čitati = to read.

So:

• ja čitam = I read / I am reading
• ti čitaš = you read
• on/ona čita = he/she reads

In this sentence, tumač čita means:

• the interpreter reads
• or the interpreter is reading, depending on context

Croatian often uses the simple present where English might use either reads or is reading.

By contrast:

• je čitao = he was reading / he read in the past

So the form is present because the sentence describes a present-time or general procedure.

Because privatnu ispravu is the direct object of čita, so it must be in the accusative case.

The basic form is:

• privatna isprava = a private document

In the accusative singular:

• privatna → privatnu
• isprava → ispravu

This happens because isprava is a feminine noun ending in -a.

So:

• nominative: privatna isprava
• accusative: privatnu ispravu

Isprava usually means an official or formal document, instrument, or certificate, especially in legal or administrative language.

It is not the most everyday word for a casual paper or file. In ordinary speech, learners often meet:

• dokument = document
• papir = paper/document informally

But isprava sounds more formal and legal.
In this sentence, that formal tone fits well with ovjera potpisa.

In legal language, privatna isprava means a private document, as opposed to a public document.

It does not necessarily mean secret or personal in the everyday sense.
It usually means a document created by private persons rather than by a public authority.

So privatna here is legal classification language, not just ordinary description.

Croatian has no articles like English a/an/the.

So a phrase like:

• tumač čita privatnu ispravu

can mean:

• the interpreter reads a private document
• the interpreter reads the private document

Which one sounds best depends on context.

Croatian relies on context, word order, and situation instead of articles.

Not completely. Croatian word order is fairly flexible because cases show grammatical relationships.

This sentence has a neutral, natural order:

• Prije ovjere potpisa tumač čita privatnu ispravu.

But other orders are possible, depending on emphasis. For example:

• Tumač čita privatnu ispravu prije ovjere potpisa.
• Privatnu ispravu tumač čita prije ovjere potpisa.

These versions are still understandable, but they may sound more marked or emphasize different parts of the sentence.

The original order is a natural way to present the time setting first:

• Before the certification of the signature, ...

No. It is a prepositional phrase, not a clause.

A clause would need a verb, but here there is no verb inside that part. It simply gives the time frame:

• prije = before
• ovjere potpisa = certification of the signature

So the sentence structure is roughly:

• Prije ovjere potpisa = time phrase
• tumač = subject
• čita = verb
• privatnu ispravu = object

Yes, but that would create a different structure.

• prije ovjere potpisa = before the certification of the signature
• prije nego što se potpis ovjeri = before the signature is certified

The first version is more compact and noun-based.
The second version is clause-based and more explicit.

Croatian often uses either style, but legal and administrative language frequently prefers the more condensed noun phrase style, like prije ovjere potpisa.

By itself, it can be understood either way.

Croatian present tense often covers:

• a general procedure
• a habitual action
• a present event

Because the sentence uses formal/legal vocabulary, it very naturally sounds like a procedural statement, something like a rule or standard step:

• Before the certification of the signature, the interpreter reads the private document.

But only the wider context can confirm that for sure.