A fogorvos fogkövet lát.

A is the Hungarian definite article, equivalent to the.

Hungarian has two forms of the definite article:

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

Since fogorvos begins with f, you say a fogorvos.

Because it is a compound noun.

• fog = tooth
• orvos = doctor

So fogorvos literally means tooth-doctor, i.e. dentist.

Hungarian very often forms compounds this way, and they are usually written as a single word.

Yes.

• fog = tooth
• kő = stone

So fogkő literally means tooth-stone. In actual usage, it means tartar or dental calculus.

This kind of literal compound structure is very common in Hungarian vocabulary.

Because fogkövet is the direct object, and Hungarian marks direct objects with the accusative ending -t.

So, very roughly:

• base form: fogkő
• object form: fogkövet

This is not just fogkő + t. The noun kő is one of those Hungarian nouns whose stem changes in some forms:

• kő
• követ
• kövek

The compound follows the same pattern:

• fogkő
• fogkövet

So the full reason is:

1. the noun is in the accusative
2. the noun kő has a stem change

It marks the direct object of the verb.

In this sentence, the thing being seen is fogkövet, so it gets the accusative ending.

Compare:

• A fogkő nagy. = The tartar is big.
  Here fogkő is the subject, so no -t.

• A fogorvos fogkövet lát. = The dentist sees tartar.
  Here fogkövet is the object, so it takes -t.

Because the object is indefinite or non-specific here.

Hungarian often leaves off the article when the object is not a specific, identified thing. So fogkövet here is more like:

• tartar
• some tartar
• dental calculus

If you wanted to refer to a specific tartar deposit already known in the conversation, you would more likely say a fogkövet.

Because Hungarian verbs have two main conjugation types:

• indefinite conjugation
• definite conjugation

Here the object is fogkövet without a definite article, so it is treated as indefinite, and the verb is lát.

Compare:

• A fogorvos fogkövet lát.
  indefinite object → lát

• A fogorvos a fogkövet látja.
  definite object → látja

This is a very important feature of Hungarian grammar.

No, Hungarian word order is fairly flexible.

A fogorvos fogkövet lát. is a neutral, straightforward sentence order.

It is basically:

• topic/subject: A fogorvos
• object: fogkövet
• verb: lát

But other orders are possible if you want to emphasize something. For example:

• Fogkövet lát a fogorvos.
  This puts more focus on fogkövet.

So word order in Hungarian is often about information structure and emphasis, not just grammar.

It is singular.

Hungarian usually marks the plural with -k. Here you only see the accusative ending -t, not a plural marker.

So:

• fogkő = singular
• fogkövet = singular accusative
• fogkövek = plural
• fogköveket = plural accusative

So in the sentence, the dentist sees one instance of tartar or tartar as a substance/category, not explicitly multiple ones.

A rough pronunciation guide is:

• A = short aw/uh sound
• fogorvos = FO-go-rvosh
• fogkövet = FOG-kø-vet
• lát = laht with a long á

A few useful points:

• Stress is normally on the first syllable of each Hungarian word.
• s in Hungarian sounds like English sh.
• ö is like German ö or French eu.

So the sentence has strong first-syllable stress:

A FOgorvos FOGkövet LÁT.

No. It just happens to be the same spelling.

In this sentence, fog is the noun tooth.

Hungarian also has another word fog as a verb form, for example:

• fog = he/she catches
• fog
  • infinitive = future-like meaning, as in will

But in fogorvos and fogkő, it is definitely the noun tooth.