A nyitvatartás hosszú.

A is the Hungarian definite article, meaning the.

So A nyitvatartás hosszú. literally starts with The opening hours/opening time...

Hungarian has two forms of the:

• a before most consonants
• az before vowels

Here it is a because nyitvatartás starts with ny.

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

So instead of saying something like The opening hours are long, Hungarian simply says:

• A nyitvatartás hosszú.

This is completely normal.

Compare:

• Én fáradt vagyok. = I am tired.
• Te fáradt vagy. = You are tired.
• Ő fáradt. = He/She is tired.

In the third person, Hungarian normally drops van/vannak in this kind of sentence.

Because Hungarian expresses this idea differently.

Nyitvatartás is a singular noun that refers to a place’s opening schedule, opening hours, or hours of operation as one concept.

English often uses a plural expression like opening hours, but Hungarian uses a singular abstract noun.

So even though the English meaning may be plural, the Hungarian grammar here is singular.

It is a compound noun built from the idea of keeping something open.

It is related to:

• nyitva tart = to keep open / to be open
• nyitvatartás = opening hours / opening schedule

A useful contrast:

• A bolt nyitva van. = The shop is open.
• A bolt nyitvatartása hosszú. = The shop’s opening hours are long.

So nyitvatartás is not just open, but the whole period or schedule of being open.

Because here it is a compound noun.

• nyitva tart = a verb phrase, to keep open
• nyitvatartás = a noun, opening hours / opening schedule

This is a very common pattern in Hungarian: a phrase can become a single compound noun when it names a concept.

So:

• A bolt sokáig nyitva tart. = The shop stays open for a long time.
• A bolt nyitvatartása hosszú. = The shop’s opening hours are long.

No. In Hungarian, adjectives used like this do not agree with the noun in number or definiteness.

So hosszú stays hosszú.

Examples:

• A nap hosszú. = The day is long.
• A napok hosszúak. = The days are long.

Notice something important: when the adjective is plural, it can take a plural ending if the subject is plural and the adjective is functioning as the predicate:

• A napok hosszúak.

But in your sentence, nyitvatartás is singular, so hosszú stays singular.

Yes, absolutely.

Both are grammatical:

• A nyitvatartás hosszú.
• Hosszú a nyitvatartás.

The difference is mainly emphasis.

• A nyitvatartás hosszú. = neutral statement: The opening hours are long.
• Hosszú a nyitvatartás. = puts more focus on long: The opening hours are long.

Hungarian word order is often flexible, and moving something earlier can make it more prominent.

Yes, it is grammatical and understandable, but in everyday speech Hungarian speakers might often say something a bit more idiomatic depending on context.

For example:

• Sokáig van nyitva. = It is open for a long time / It stays open late.
• Hosszú a nyitvatartása. = Its opening hours are long.

If you are talking about a specific place, Hungarian often prefers the possessed form:

• Az üzlet nyitvatartása hosszú.
• Hosszú az üzlet nyitvatartása.

So your sentence is fine, but context may make another version sound more natural.

Because it is the subject of the sentence, so it is in the basic dictionary form, which is the nominative.

Hungarian often shows grammar with endings, but the subject itself usually has no special ending.

So:

• nyitvatartás = subject, basic form
• hosszú = predicate adjective

There is no extra case ending needed here.

A very natural way is:

• A bolt nyitvatartása hosszú.

Here:

• bolt = shop
• nyitvatartása = its opening hours

The ending -a/-e/-ja/-je can show possession, so nyitvatartása means its opening hours.

This is often more specific and natural than using A nyitvatartás... by itself.

Roughly:

nyit-va-tar-taash

A few pronunciation notes:

• ny is like the ny sound in Spanish señor or the n in British pronunciation of new for some speakers.
• i is like ee in see, but shorter.
• a is a short open vowel, not like English ay.
• á is a long vowel, roughly aa.
• The stress in Hungarian is always on the first syllable:

NYIT-va-tar-tás

Yes. Hosszú can describe both:

• physical length
• duration
• something extended in time

In this sentence it refers to duration/schedule, not physical size.

So A nyitvatartás hosszú. means the opening period is long, not that something is physically long.

Yes. You can make the opposite sentence by replacing hosszú with rövid:

• A nyitvatartás rövid. = The opening hours are short.

This works in exactly the same grammatical pattern:

• definite article
• subject noun
• predicate adjective
• no present-tense is/are in the third person