A katolikus közösség nagy.

In Hungarian, the verb to be is often left out in the present tense, third person.

So:

• A közösség nagy = The community is big
• literally: The community big

This is completely normal in Hungarian.

But the verb appears in other persons, for example:

• Én nagy vagyok = I am big
• Te nagy vagy = You are big
• A közösség nagy = The community is big

So in your sentence, the missing is is not really missing—Hungarian just does not say it here.

A is the Hungarian definite article, meaning the.

So:

• a közösség = the community

Hungarian has two forms of the:

• a
• az

Which one is used depends on the following sound:

• a before most consonant sounds: a közösség
• az before vowel sounds: az iskola

So A katolikus közösség nagy starts with a because katolikus begins with a consonant sound.

In Hungarian, adjectives of religion, nationality, and language are usually written with a lowercase letter, unless they begin a sentence.

So:

• katolikus = Catholic
• magyar = Hungarian
• angol = English

Because this sentence begins with A, not katolikus, the word katolikus stays lowercase.

Because katolikus is an adjective modifying the noun közösség.

In Hungarian, attributive adjectives usually come before the noun, just as they do in English:

• katolikus közösség = Catholic community
• nagy ház = big house
• szép város = beautiful city

So:

• katolikus describes what kind of community
• nagy tells us what the community is like

Here nagy is the predicate adjective: it says something about the subject.

Structure:

• A katolikus közösség = the subject
• nagy = what is being said about it

So the sentence pattern is basically:

• [The Catholic community] [big]

This is normal Hungarian word order for a simple neutral statement.

No. Hungarian adjectives do not agree the way adjectives do in many Indo-European languages.

That means the adjective usually keeps the same form:

• nagy közösség = big community
• nagy közösségek = big communities

Notice that nagy stays nagy.

Hungarian has no grammatical gender, so there is no masculine/feminine/neuter adjective agreement either.

Közösség usually means community.

Depending on context, it can refer to:

• a religious community
• a social group
• a local community
• a shared community of people

In your sentence, katolikus közösség most naturally means Catholic community.

A rough pronunciation guide:

• kö sounds somewhat like the vowel in French peu or German schön
• zö has the same ö sound
• ss in Hungarian is pronounced like English sh
• ég has a long é, like a longer ay sound, followed by g

So approximately:

• kö-zö-shayg

A more careful breakdown:

• kö-zö-sség
• with stress on the first syllable: KÖ-zö-sség

Hungarian always stresses the first syllable of the word.

Hungarian spelling is different from English spelling.

Some useful patterns:

• s = sh
• sz = s
• zs = the s in measure
• cs = ch

So in közösség, the ss is a long version of Hungarian s, which sounds like sh.

That is why the word sounds roughly like kö-zö-shayg.

Because közösség is a singular noun meaning community—one collective group.

Hungarian, like English, can use a singular noun for a group:

• a közösség = the community
• a család = the family
• a csapat = the team

If you wanted communities, you would say:

• közösségek = communities

So A katolikus közösség nagy means The Catholic community is big, referring to one community.

Yes, but it means something slightly different in emphasis and structure.

• A katolikus közösség nagy = The Catholic community is big
  • katolikus describes which community
• A közösség katolikus = The community is Catholic
  • katolikus is now what you are saying about the community

So the same adjective can appear in two different roles:

1. before the noun: attributive adjective

   • katolikus közösség = Catholic community

2. after the noun / as predicate: predicate adjective

   • A közösség katolikus = The community is Catholic

This sentence is quite neutral and straightforward.

• A katolikus közösség nagy.

It simply states a fact: the Catholic community is large.

Hungarian word order can change for emphasis, but this version is the normal, unmarked way to say it.

Sometimes yes, depending on context.

Nagy can mean:

• big / large
• sometimes great in certain expressions

But in this sentence, the most natural meaning is big or large:

• A katolikus közösség nagy = The Catholic community is big / large

If the intended meaning were great in the sense of excellent, Hungarian would often use a different word depending on context, such as nagyszerű.

The pattern is:

• A katolikus közösség = noun phrase subject
• nagy = predicate adjective

So the whole structure is:

• [Definite article + adjective + noun] + [predicate adjective]

More abstractly:

• The Catholic community + big

This is a very common Hungarian sentence type, especially in the present tense where is is omitted in the third person.