A barátom a győztes.

In Hungarian, the verb to be is usually left out in the present tense, third person singular when the sentence is something like X is Y.

So Hungarian says:

A barátom a győztes.
literally: My friend the winner.

But it means My friend is the winner.

This omission only happens in certain forms. For example:

• Én vagyok a győztes. = I am the winner.
• Te vagy a győztes. = You are the winner.
• A barátom volt a győztes. = My friend was the winner.

So in your sentence, leaving out is is completely normal.

It is one word, made up of:

• barát = friend
• -om = my

So barátom literally means friend-my, which is how Hungarian expresses possession.

Hungarian usually puts the possessive ending directly on the noun, instead of using a separate word like my.

A few examples:

• barát = friend
• barátom = my friend
• barátod = your friend
• barátja = his/her friend

So A barátom is my friend.

Because a is the Hungarian definite article, like the in English.

Here:

• a barátom = my friend
• a győztes = the winner

English does not usually say the my friend, but Hungarian can use the definite article before a possessed noun:

• a barátom = my friend
• a könyvem = my book

That is normal Hungarian.

The second a is there because győztes is also definite here: not just a winner, but the winner.

Hungarian has two forms of the definite article:

• a before a consonant
• az before a vowel

Since both barátom and győztes begin with consonants, the article is a.

Examples:

• a barátom
• a győztes
• but az alma = the apple
• az ember = the person

So the choice depends only on the next sound.

In this sentence:

• A barátom = the subject/topic
• a győztes = the predicate noun

So the structure is basically:

My friend = the winner

Hungarian often uses this kind of sentence to identify someone or something.

Because both parts are definite, English speakers sometimes wonder how Hungarian tells them apart. Usually it is done by word order and context.

In A barátom a győztes, the natural interpretation is:

• we are talking about my friend
• and saying that he is the winner

Yes, and it is grammatically correct, but the focus of the sentence changes.

• A barátom a győztes = My friend is the winner
• A győztes a barátom = The winner is my friend

The basic fact is the same, but the starting point is different:

• first sentence: we begin with my friend
• second sentence: we begin with the winner

Hungarian word order is strongly connected to topic and focus, not just grammar.

You may see that kind of omission in special styles, but in normal neutral Hungarian, A barátom a győztes is the standard form.

Leaving out the first article can sound:

• more literary
• more compressed
• more context-dependent
• or less neutral

So for a learner, the safest version is:

A barátom a győztes.

There is a difference in meaning or nuance.

• A barátom a győztes. = My friend is the winner
  This identifies him as the specific winner.

• A barátom győztes. = more like My friend is victorious / a winner-type person / winning
  This is less natural if you mean a specific contest winner.

So with a győztes, Hungarian is making a clear identification: he is the one who won.

Roughly:

dyur-ztesh is not exact, but it helps a little for an English speaker.

A few important pronunciation points:

• gy is a soft consonant sound that English does not have exactly
• ő is a long vowel, somewhat like a rounded version of the vowel in French peu or German schön
• s in Hungarian is pronounced sh
• sz is the plain s sound in English, but note that this word ends in s, not sz

So győztes ends with a sh sound.

Also, Hungarian stress is normally on the first syllable, so:

GYŐZ-tes

It can depend on context.

barátom can mean:

• my friend
• sometimes my boyfriend

Usually the situation makes it clear.

Related words:

• barát = male friend / boyfriend
• barátnő = female friend / girlfriend
• barátom = my friend / my boyfriend
• barátnőm = my female friend / my girlfriend

So if the meaning shown to the learner is my friend, that is perfectly normal, but context can allow other interpretations.