Neograničeni pozivi su važni.

A natural word-by-word breakdown is:

• Neograničeni = unlimited
• pozivi = calls
• su = are
• važni = important

So the structure is:

• Neograničeni pozivi = the subject, unlimited calls
• su važni = the predicate, are important

Croatian often looks very straightforward in sentences like this: subject + form of "to be" + adjective.

Because Croatian does not have articles like English a/an/the.

So Neograničeni pozivi can mean:

• Unlimited calls in general
• or, depending on context, the unlimited calls

Usually the context tells you whether the meaning is general or specific. In this sentence, it most naturally sounds like a general statement: Unlimited calls are important.

Yes.

• singular: poziv = call
• plural: pozivi = calls

So if you wanted the singular sentence, it would be:

• Neograničeni poziv je važan. = An unlimited call is important.

Notice that when the noun changes from singular to plural, the verb and adjective also change.

Pozivi is in the nominative plural.

You can tell it is the subject because:

• it matches the plural verb su = are
• the sentence is describing what pozivi are like
• važni agrees with it as a predicate adjective

So the basic logic is:

• pozivi = the thing being talked about
• su važni = what is being said about them

Because it has to agree with pozivi.

In Croatian, adjectives agree with the noun they describe in:

• gender
• number
• case

Here:

• pozivi is masculine plural nominative
• so neograničeni must also be masculine plural nominative

That is why you see neograničeni pozivi.

Because važni has to agree with the subject pozivi, which is plural.

Compare:

• poziv je važan = the call is important
  
  • singular masculine
• pozivi su važni = the calls are important
  
  • plural masculine

So:

• važan = singular masculine
• važni = plural masculine

Even though važni comes after the verb, it still agrees with the subject.

Su is the 3rd person plural present tense of biti = to be.

So:

• je = is
• su = are

Examples:

• Poziv je važan. = The call is important.
• Pozivi su važni. = The calls are important.

In standard Croatian, you normally do need su here. You cannot simply leave it out.

Yes, Croatian word order is fairly flexible, but su is a clitic, and clitics usually go in second position.

That is why the neutral sentence is:

• Neograničeni pozivi su važni.

You can also change the order for emphasis, for example:

• Važni su neograničeni pozivi. = emphasis on important
• Neograničeni pozivi važni su is much less natural in normal usage

So the given sentence is the most neutral and natural version.

A rough English-friendly guide:

• Neograničeni = neh-oh-grah-nee-CHEH-nee
• pozivi = poh-ZEE-vee
• su = soo
• važni = VAZH-nee

Useful sounds:

• č sounds like ch in church
• ž sounds like the s in measure

So važni starts with a sound like vazh-.

In this sentence, yes, most likely.

The noun poziv can mean different kinds of call, depending on context, such as:

• a phone call
• an invitation
• a calling/vocation in some contexts

But with neograničeni = unlimited, the most natural meaning is unlimited phone calls, like in a mobile plan or service package.

Yes, you could, but the nuance is slightly different.

• važni = important
• bitni = essential / important / significant

In many everyday contexts, they can overlap. But važni is the most direct match for English important here.

So:

• Neograničeni pozivi su važni. = the clearest standard version for Unlimited calls are important.