A parkolási engedély érvényes.

Word by word:

• A = the
• parkolási = parking / related to parking
• engedély = permit, license, authorization
• érvényes = valid

So the structure is literally:

• The parking permit valid

In natural English, that becomes The parking permit is valid.

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

So:

• A parkolási engedély érvényes. = The parking permit is valid.

But in other persons, Hungarian does use the verb:

• Érvényes vagyok. = I am valid
• Érvényes vagy. = You are valid

And in past or future, van / volt / lesz appears as needed:

• A parkolási engedély érvényes volt. = The parking permit was valid.

This missing is is one of the most important things for English speakers to get used to.

Parkolási is an adjective-like form meaning parking-related.

It comes from:

• parkol = to park
• parkolás = parking (the act of parking)
• parkolási = parking-, related to parking

So:

• parkolási engedély = parking permit
• literally, something like permit for parking

This -i ending is very common in Hungarian for making a descriptive word from a noun:

• iskola = school → iskolai = school-related
• város = city → városi = city-related
• parkolás = parking → parkolási = parking-related

Because parkolási engedély and parkolóengedély would suggest different things.

• parkolási means related to parking
• parkoló usually means parking lot or someone/something that is parking

So:

• parkolási engedély = parking permit
• parkoló by itself often means car park / parking area

Hungarian often uses -ási / -ési forms when talking about an activity in an abstract or official way, especially in compounds and formal expressions.

Yes. A is the definite article the.

Hungarian has two forms of the definite article:

• a
• az

Which one is used depends on the following sound:

• a before a consonant: a parkolási engedély
• az before a vowel: az engedély

So here it is a because parkolási starts with p, a consonant.

Yes, if the context already makes it clear which permit you mean.

• Az engedély érvényes. = The permit is valid.
• A parkolási engedély érvényes. = The parking permit is valid.

The second version is more specific because it tells you what kind of permit it is.

No. Hungarian adjectives do not agree with nouns in the same way they do in many Indo-European languages.

So érvényes stays the same:

• az engedély érvényes = the permit is valid
• az engedélyek érvényesek = the permits are valid

Notice something important:

• Before the noun: adjectives usually stay unchanged
  
  • érvényes engedély = valid permit
• As the predicate: adjectives can take plural marking when the subject is plural
  
  • Az engedélyek érvényesek. = The permits are valid.

So in your sentence, singular subject → singular predicate adjective: érvényes.

Yes.

• érvényes engedély = a valid permit
• Az engedély érvényes. = The permit is valid.

This is similar to English:

• a valid permit
• the permit is valid

So érvényes works both attributively and predicatively.

A parkolási engedély érvényes is the neutral, straightforward word order:

• subject: A parkolási engedély
• predicate/adjective: érvényes

You can rearrange Hungarian word order for emphasis, but the neutral version is the most natural in basic learning contexts.

For example:

• Érvényes a parkolási engedély.

This is possible, but it gives a slightly different focus, something like emphasizing valid.

For most learners, the safest basic pattern is:

• [noun phrase] + [adjective]

A simple learner-friendly pronunciation guide:

• A = short aw
• parkolási ≈ PAR-ko-laa-shee
• engedély ≈ EN-ghe-day
• érvényes ≈ AIR-vay-nyesh

A few pronunciation notes:

• s in Hungarian sounds like English sh
• sz sounds like English s
• ny is like the ny in canyon
• é is a long vowel, roughly like ay
• Stress is always on the first syllable of each word:
  • PARkolási
  • ENgedély
  • AIRvényes

It can mean any of those depending on context, but in this sentence permit is usually the most natural translation.

• engedély = permit / permission / authorization / license

So:

• parkolási engedély is most naturally parking permit

In official or legal contexts, English may choose different words, but permit is the clearest everyday choice here.

You add nem before the adjective:

• A parkolási engedély nem érvényes. = The parking permit is not valid.

This is a very common pattern in Hungarian:

• A jegy érvényes. = The ticket is valid.
• A jegy nem érvényes. = The ticket is not valid.

You can add adverbs or other expressions after the adjective, or elsewhere depending on focus.

Examples:

• A parkolási engedély itt érvényes. = The parking permit is valid here.
• A parkolási engedély ma érvényes. = The parking permit is valid today.
• A parkolási engedély még érvényes. = The parking permit is still valid.

Hungarian is flexible with word order, but these are good basic versions.

Yes, it sounds perfectly natural, especially in an official or administrative context.

Hungarian often uses short, direct statements like this in notices and formal communication:

• A jegy érvényes. = The ticket is valid.
• A bérlet érvényes. = The pass is valid.
• A parkolási engedély érvényes. = The parking permit is valid.

It is concise and standard Hungarian.