A tanú is itt van.

Both a and az mean the.

Hungarian uses:

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

Since tanú begins with t, you say a tanú = the witness.

Examples:

• a tanú = the witness
• az ember = the person

This has nothing to do with gender; Hungarian articles do not change for masculine/feminine.

No. This is one of the easiest things to confuse.

In A tanú is itt van, the word is means also / too / as well.

The actual verb is / is present is van.

So the sentence breaks down like this:

• a tanú = the witness
• is = also, too
• itt = here
• van = is

So is is a particle, not the verb.

Because Hungarian is normally goes directly after the word or phrase it adds also/too to.

So:

• A tanú is = the witness too / the witness also

This tells you that the witness is the thing being added.

That is a very important pattern in Hungarian:

• Péter is itt van. = Peter is here too.
• A tanú is itt van. = The witness is here too.

If you move is, you change what also applies to.

In this sentence, it applies to the witness, because it follows a tanú.

So the structure is:

• A tanú is = the witness too
• itt van = is here

If you wanted here too, Hungarian would normally put is after itt:

• A tanú itt is van.

That changes the emphasis/scope of also.

So word placement matters a lot with is.

Itt means here.

It is a place adverb, not a noun, so it does not need an article.

A useful contrast is:

• itt = here
• ott = there
• ide = to here
• oda = to there

So in this sentence, itt van means is here or is present here.

That is true in some cases, but not in all cases.

Hungarian often omits van in the 3rd person singular/plural present when the predicate is a noun or adjective:

• A tanú fáradt. = The witness is tired.
• A tanú ügyvéd. = The witness is a lawyer.

But with location or existence, Hungarian normally uses van:

• A tanú itt van. = The witness is here.
• A tanú otthon van. = The witness is at home.

So van is necessary here because itt expresses location.

Not completely. Hungarian word order is flexible, but different orders usually change the emphasis.

A tanú is itt van is a natural, safe way to say it.

Why this order works well:

• A tanú is sets up the thing being talked about: the witness too
• itt van gives the main statement: is here

If you move things around, the sentence may still be grammatical, but it can sound marked, contrastive, or less neutral.

So for a learner, A tanú is itt van is the best default form.

Usually no, not if you mean the witness.

A tanú is the normal way to say the witness.

If you mean a witness, you would usually say:

• egy tanú = a witness

So compare:

• A tanú is itt van. = The witness is here too.
• Egy tanú is itt van. = A witness is here too.

Leaving out the article entirely would usually sound unnatural in an ordinary sentence like this.

A good approximate pronunciation is:

[ɒ ˈtɒnuː iʃ itː vɒn]

A few helpful points:

• Hungarian stress is usually on the first syllable of each word.
• tanú is pronounced roughly TA-noo.
• ú is long, like oo in food, but held a bit longer.
• is is pronounced like ish, not like the English verb is.
• itt has a doubled tt, so the final consonant is longer/stronger than in English it.

So you can think of it roughly as:

aw TAH-noo ish itt von

That is only approximate, but it is close enough for a beginner.

Then you would place is after itt:

• A tanú itt is van.

That means something like:

• The witness is here too
• The witness is also here

The difference is subtle in English, but very clear in Hungarian:

• A tanú is itt van. = The witness too is here.
• A tanú itt is van. = The witness is here too.

So in Hungarian, the position of is tells you what also/too belongs to.