A szakkönyv részletes.

Because Hungarian usually omits the verb to be in the present tense, third person when the predicate is a noun or an adjective.

So:

• A szakkönyv részletes. = The professional/technical book is detailed.

But in other persons or tenses, the verb does appear:

• A szakkönyv részletes volt. = The book was detailed.
• Én részletes vagyok. = I am detailed (grammatically possible, though not very natural in meaning)

This is one of the first things English speakers notice, because English requires is, but Hungarian often does not here.

A is the definite article, so it means the.

Hungarian has two forms of the definite article:

• a before a consonant sound
• az before a vowel sound

So:

• a szakkönyv = the technical/professional book
• az iskola = the school

Since szakkönyv begins with sz, which is a consonant sound, a is the correct form.

Yes, szakkönyv is a single compound word.

It is made from:

• szak = field, specialty, profession
• könyv = book

Together, szakkönyv means a book related to a specialized field, such as a technical, specialist, or professional book.

Hungarian very often writes compounds as one word, so this is completely normal.

The double k comes from the compound:

• szak
• könyv

When they join, the k at the end of szak and the k at the beginning of könyv meet, so you get szakkönyv.

In pronunciation, this is a longer consonant, not just a spelling quirk. Hungarian pays attention to consonant length, so the double letter matters.

In this sentence, részletes stays in its basic form because the subject is singular, and Hungarian does not have grammatical gender.

A few important points:

• Hungarian adjectives do not change for masculine/feminine/neuter, because Hungarian has no grammatical gender
• In a sentence like this, with a singular subject, the adjective stays singular too

So:

• A szakkönyv részletes. = singular
• A szakkönyvek részletesek. = plural

Notice that in the plural, the adjective can take a plural ending when it is the predicate.

A rough guide:

• sz is pronounced like English s
• s by itself is pronounced like English sh
• ny is a soft sound, similar to ny in canyon
• é is a long ay/eh-type vowel
• ö has no exact English equivalent; it is similar to German ö or French eu
• Stress in Hungarian is almost always on the first syllable

Very rough pronunciation:

• szakkönyv ≈ SOKK-könyv (with a rounded ö sound)
• részletes ≈ RAY-sleh-tesh

A more accurate IPA-style version would be approximately:

• a szakkönyv részletes = [ɒ ˈsɒkːøɲv ˈreːsleteʃ]

Yes, you can.

Both are grammatical, but the emphasis changes:

• A szakkönyv részletes. = neutral statement
• Részletes a szakkönyv. = puts more emphasis on detailed

Hungarian word order is much more flexible than English word order, and it often reflects topic and focus, not just grammar.

So the original sentence is the most neutral, dictionary-style version.

Részletes is an adjective.

Here it is used predicatively, meaning it comes after the subject and describes it:

• A szakkönyv részletes.

That is different from using it directly before a noun:

• a részletes szakkönyv = the detailed technical book

So the same adjective can appear:

• before a noun: a részletes szakkönyv
• as the predicate: A szakkönyv részletes

You would say:

A szakkönyvek részletesek.

Changes:

• szakkönyv → szakkönyvek = books
• részletes → részletesek = detailed in plural predicate form

So:

• A szakkönyv részletes. = The book is detailed.
• A szakkönyvek részletesek. = The books are detailed.

Notice that there is still no separate word for are in the present tense.

Yes, absolutely.

A szakkönyv részletes. is a perfectly complete Hungarian sentence. Even though it feels short to an English speaker, it is fully natural because:

• the article is there: a
• the subject is there: szakkönyv
• the predicate adjective is there: részletes
• the verb is is simply omitted by a normal Hungarian rule

So although it may look like something is missing from an English perspective, nothing is missing in Hungarian.