A fogköz kicsi.

A is the definite article, equivalent to the in English.

Hungarian has two forms of the definite article:

• a before a consonant
• az before a vowel

Since fogköz starts with f, the correct form is a: A fogköz.

In Hungarian, the verb to be is often omitted in the present tense, especially in the 3rd person, when the predicate is a noun or an adjective.

So:

• A fogköz kicsi. = The tooth gap is small.

Even though there is no written word for is, it is understood.

You would use forms of van in other situations, for example in the past or future:

• A fogköz kicsi volt. = The tooth gap was small.
• A fogköz kicsi lesz. = The tooth gap will be small.

Yes, fogköz is one word. It is a compound noun.

It is made from:

• fog = tooth
• köz = space / gap / interval

So literally it means something like tooth-gap, that is, the gap between teeth.

Hungarian very often writes compound nouns as a single word.

Because here kicsi is not directly modifying the noun inside a noun phrase. It is the predicate of the sentence.

Compare:

• A fogköz kicsi. = The tooth gap is small.
• A kicsi fogköz = the small tooth gap

So:

• after the noun: sentence meaning is small
• before the noun: adjective directly attached to the noun

This is a very important difference in Hungarian.

Both are related to the idea of small, but they are not used in exactly the same way.

• kicsi is the full adjective
• kis is a shorter form used very often before a noun

So:

• A fogköz kicsi. is natural and correct.
• kis fogköz can mean small tooth gap.

After the noun, as the predicate of the sentence, kicsi is the normal form. You would not normally say A fogköz kis.

A rough pronunciation guide is:

• a = a short aw/uh sound
• fog = fohg
• köz = the ö is like German ö or French eu; z sounds like z in zoo
• kicsi = KEE-chee

A rough overall guide would be:

aw FOG-köz KEE-chee

Also, Hungarian normally stresses the first syllable of each word:

• A
• FOGköz
• KIcsi

Yes, you can.

• A fogköz kicsi. is a neutral statement.
• Kicsi a fogköz. puts more focus on kicsi.

That second version can sound a bit more like:

• The gap is small
• It’s small, the gap

So both are grammatical, but the word order changes the emphasis.

You add nem before the predicate:

• A fogköz nem kicsi. = The tooth gap is not small.

Since there is no written is in the positive sentence, you do not need to change any verb here. You just insert nem.

The plural forms would be:

• fogközök = tooth gaps
• kicsik = small in the plural

So the sentence becomes:

• A fogközök kicsik. = The tooth gaps are small.

Notice that both the noun and the adjective become plural.