A világ tele van kerékpárokkal.

A word-by-word breakdown is:

• a = the
• világ = world
• tele van = is full
• kerékpárokkal = with bicycles

So Hungarian structures this a little differently from English. A very literal version is something like:

The world is full with bicycles

In natural English, of course, we say full of bicycles.

A / az is the Hungarian definite article, meaning the.

• a is used before a consonant sound
• az is used before a vowel sound

Since világ starts with v, Hungarian uses a világ.

Examples:

• a ház = the house
• az autó = the car

Tele means full, and van means is.

Together, tele van is the normal Hungarian way to say is full:

• A pohár tele van. = The glass is full.
• A szoba tele van emberekkel. = The room is full of people.

So even though English uses full as one adjective, Hungarian often uses this fixed pattern:

tele van + something in -val/-vel

That is a very common learner question.

It is true that in Hungarian, the present-tense to be is often omitted in 3rd person:

• A ház nagy. = The house is big.
• Anna tanár. = Anna is a teacher.

But with tele, Hungarian normally uses the full expression tele van.

So:

• A világ tele van kerékpárokkal. is normal.
• A világ tele kerékpárokkal. is not standard.

You can think of tele van as a set expression meaning to be full of.

Because Hungarian does not express this idea with a separate word like English of.

Instead, after tele van, Hungarian puts the noun into the -val / -vel case, which often means with.

So:

• tele van vízzel = full of water
• tele van emberekkel = full of people
• tele van kerékpárokkal = full of bicycles

So kerékpárokkal literally looks like with bicycles, even though the whole phrase means full of bicycles.

It breaks down like this:

• kerékpár = bicycle
• kerékpárok = bicycles
• kerékpárokkal = with bicycles

More exactly:

• kerékpár
• • -ok plural
• • -val / -vel ending

This would historically give something like kerékpárokval, but Hungarian changes it through consonant assimilation:

• the v of -val/-vel often disappears
• and the previous consonant is doubled

So:

• kerékpárok + val → kerékpárokkal

This is very normal in Hungarian:

• ház + val → házzal
• kéz + vel → kézzel
• ablak + kal → ablakkal

Because the sentence is talking about many individual bicycles.

Hungarian does sometimes use the singular where English uses a plural, but not in this kind of sentence. Here, plural is the natural choice:

• tele van könyvekkel = full of books
• tele van autókkal = full of cars
• tele van kerékpárokkal = full of bicycles

A singular form such as kerékpárral would sound like full of bicycle or would suggest a different kind of meaning, not the normal idea here.

Yes.

• kerékpár = more formal or standard
• bicikli = very common everyday word for bicycle / bike

So this is also natural:

A világ tele van biciklikkel.

The meaning stays basically the same, but bicikli sounds a bit more colloquial and everyday.

Yes, Hungarian word order is flexible, but changing it changes the emphasis.

The neutral sentence is:

A világ tele van kerékpárokkal.

This presents a világ as the topic, and then says something about it.

You can also say:

Kerékpárokkal van tele a világ.

This puts more emphasis on kerékpárokkal and feels closer to:

It’s bicycles that the world is full of.

So the original version is the most neutral and straightforward one, while other word orders are possible if you want a different focus.