A tó mellett a táj nagyon szép.

A is the Hungarian definite article, meaning the.

It appears twice because there are two definite noun phrases here:

• a tó mellett = beside the lake
• a táj = the landscape / the scenery

Hungarian normally uses the article separately with each noun phrase, just as English does here.

A useful extra point: Hungarian has two forms of the:

• a before a consonant
• az before a vowel

So here it is a tó and a táj because both nouns begin with consonants.

In Hungarian, the present-tense third-person form of to be is often omitted when the predicate is a noun or adjective.

So:

• A táj nagyon szép. = The landscape is very beautiful.

There is no need to say van here.

But compare:

• A táj a tó mellett van. = The landscape is next to the lake.

Here van appears because the sentence is about location, not just description.

So in your sentence, szép is the main predicate adjective, and that is why there is no separate word for is.

Mellett means beside, next to, or sometimes by.

It comes after the noun because Hungarian often uses postpositions instead of English-style prepositions.

So:

• English: beside the lake
• Hungarian: a tó mellett
• literally: the lake beside

This is completely normal in Hungarian. Many common location words work this way.

Because mellett itself expresses the relationship, the noun usually stays in its basic form.

So:

• a tó mellett = beside the lake

The noun tó does not need an extra case ending here.

This is a common pattern with postpositions in Hungarian: the postposition carries the meaning that English would express with a preposition.

A learner may compare this with forms like tónál, which means something more like at the lake / by the lake, but that is a different construction and not exactly the same as mellett.

Táj means landscape, scenery, or the surrounding countryside/region, depending on context.

In this sentence, a táj most naturally means:

• the landscape
• the scenery

It is broader than just a single view. It refers more to the natural scene or area.

Hungarian word order is flexible, and the first part of the sentence often sets the scene or topic.

So starting with A tó mellett gives a sense like:

• By the lake, the landscape is very beautiful
• As for the area next to the lake, the scenery is very beautiful

This is very natural Hungarian word order.

You could also say something like:

• A táj a tó mellett nagyon szép

but that puts the focus a bit differently. The original sentence first establishes the location, then comments on the landscape there.

Nagyon means very.

It normally goes before the adjective or adverb it modifies:

• nagyon szép = very beautiful

So in this sentence:

• a táj nagyon szép = the landscape is very beautiful

This is the standard position.

Its core meaning is beside or next to.

In some English translations, it may come out as near or by, depending on what sounds most natural. But mellett usually suggests being at the side of something, not just vaguely nearby.

So:

• a tó mellett most literally = beside the lake / next to the lake

A few useful pronunciation points:

• sz is pronounced like English s
• j is pronounced like English y
• gy in nagyon is a soft sound, roughly like dy
• accented vowels such as ó, á, é are long

Very rough approximation:

• A tó mellett a táj nagyon szép
  ≈ aw toh MELL-ett aw taay NOD-yon sayp

That is only approximate, but it helps with the main sounds.