A girland hosszú.

No. In Hungarian, a here means the, not English a/an.

• a girland = the garland
• Hungarian has two forms of the definite article:
  • a before consonants
  • az before vowels

So it is a girland, but for example az alma = the apple.

Because Hungarian usually leaves out is in the present tense, third person when the predicate is a noun or an adjective.

So:

• A girland hosszú. = The garland is long.

There is no van here.

Compare:

• Én hosszú vagyok would be ungrammatical in this meaning, but with adjectives in 1st/2nd person you do use the verb:
  • Én boldog vagyok. = I am happy.
  • Te boldog vagy. = You are happy.
• But in 3rd person:
  • Ő boldog. = He/She is happy.

So the missing is is completely normal.

Hungarian adjectives come before the noun when they directly describe it inside a noun phrase, but they come after the noun when they are part of the predicate.

Here:

• A girland hosszú. = The garland is long.
  • hosszú is a predicate adjective

But:

• a hosszú girland = the long garland
  • here hosszú directly modifies girland

So the position changes depending on the structure.

Girland is a noun meaning garland.

In this sentence it is the subject, and it appears in its basic dictionary form. Hungarian does not add a special ending for the nominative subject form in a sentence like this.

So:

• girland = garland
• a girland = the garland

A rough English-friendly approximation is:

aw GEER-land HOSS-soo

A few helpful notes:

• Stress in Hungarian is almost always on the first syllable of each word.
• g is a hard g.
• i is like ee in see.
• sz is pronounced like English s.
• The final ú is a long oo sound.

So hosszú sounds roughly like HOSS-soo.

Because girland begins with a consonant.

Hungarian uses:

• a before consonant sounds
• az before vowel sounds

Examples:

• a girland = the garland
• a ház = the house
• az alma = the apple
• az ember = the person

Yes. Hungarian word order is flexible, and changing it often changes the emphasis.

• A girland hosszú. is a neutral statement: The garland is long.
• Hosszú a girland. also means The garland is long, but it puts more focus on long.

So both are possible, but the first version is the most straightforward neutral one.

Not exactly.

• A girland hosszú. = The garland is long.
• A hosszú girland = the long garland

The first is a full sentence.
The second is just a noun phrase, not a complete sentence by itself.

So they are related, but they are not the same structure.