Vlasnik računa bi potvrdio identitet ličnim dokumentom.

Bi potvrdio is the conditional form of the verb potvrditi (to confirm).

In this sentence, it most naturally means something like:

• would confirm
• would verify

In formal or procedural language, Serbian often uses this form to describe what someone would do in a given situation or step in a process.

Also, potvrdio is the masculine singular form, agreeing with vlasnik (owner / holder).

Because vlasnik usually takes the genitive case to show what someone owns.

So:

• vlasnik = owner
• računa = of the account

The base form is račun (account / bill), but after vlasnik it becomes računa, which is the genitive singular.

So vlasnik računa literally means owner of the account.

Here, identitet is in the accusative case because it is the direct object of potvrdio:

• potvrditi šta? = to confirm what?
• identitet = identity

It looks the same as the nominative because identitet is a masculine inanimate noun. In Serbian, many masculine inanimate nouns have the same form in:

• nominative singular
• accusative singular

So:

• nominative: identitet
• accusative: identitet

Because ličnim dokumentom is in the instrumental case.

The instrumental here expresses the means or instrument used to do something:

• potvrditi identitet ličnim dokumentom
• to confirm identity with a personal document / by means of an ID document

The dictionary forms are:

• lični = personal
• dokument = document

In the instrumental singular, they become:

• ličnim
• dokumentom

Both words change because the adjective must agree with the noun in:

• case
• gender
• number

Not exactly. Lični dokument is a broader term meaning personal identification document.

Depending on context, it could mean:

• an ID card
• a passport
• another official identity document

If Serbian specifically wants to say ID card, it often uses lična karta.

So in this sentence, ličnim dokumentom is best understood as with an identity document or with a personal ID document.

The participle potvrdio is masculine singular because it agrees with vlasnik, which is a masculine noun.

If the sentence referred specifically to a female owner, you would normally say:

• Vlasnica računa bi potvrdila identitet ličnim dokumentom.

So:

• vlasnik ... bi potvrdio = male owner would confirm
• vlasnica ... bi potvrdila = female owner would confirm

In formal or generic statements, Serbian often uses the masculine form as the default.

The basic verb is potvrditi, which is perfective.

That means it refers to a completed action: to confirm / to verify successfully.

Its imperfective partner is usually potvrđivati, meaning to be confirming, to confirm repeatedly, or to confirm in an ongoing sense.

So here:

• potvrditi fits well because confirming identity is seen as a single completed act.

It can mean both, depending on context.

Common meanings of račun include:

• account (bank account, user account)
• bill
• check
• invoice

In vlasnik računa, the context strongly points to account holder / owner of the account, not owner of the bill.

So here računa should definitely be understood as of the account.

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

This sentence could be rearranged, for example:

• Vlasnik računa bi identitet potvrdio ličnim dokumentom.
• Identitet bi vlasnik računa potvrdio ličnim dokumentom.

These versions are grammatically possible, but they may sound more marked or shift the emphasis.

The original order:

• Vlasnik računa bi potvrdio identitet ličnim dokumentom.

is neutral and natural in formal written language.

It sounds quite formal and somewhat bureaucratic / administrative.

That is normal for contexts such as:

• banks
• legal documents
• official procedures
• customer verification rules

In more everyday speech, a Serbian speaker might choose a simpler or more direct wording, depending on the situation. But for official language, this sentence sounds natural.

Yes. Although bi + participle is formally the conditional, in official instructions it can sound less like a hypothetical would and more like:

• would
• should
• would normally
• would in that case

So the sentence may describe a standard procedure rather than an unreal condition.

That is why translations can vary a little depending on context, even though the Serbian form is the same.

They are:

• vlasnik = owner, holder
• račun = account, bill
• biti = to be → here in the form bi
• potvrditi = to confirm, verify
• identitet = identity
• lični = personal
• dokument = document

This can help you see how much Serbian changes words by case and verb form.