Bibliotekoj ekzistas tra la mondo.

Because -o marks a noun in Esperanto, and -j marks the plural.

So:

• biblioteko = library
• bibliotekoj = libraries

The ending -oj is pronounced roughly like oy in English.

In Esperanto, all present-tense verbs end in -as.

So:

• ekzisti = to exist
• ekzistas = exists / exist

The verb ending does not change for different subjects. That means:

• mi ekzistas = I exist
• ĝi ekzistas = it exists
• bibliotekoj ekzistas = libraries exist

This is much simpler than English, where exist and exists are different forms.

Estas means is/are, while ekzistas means exists/exist.

In this sentence, Esperanto is using the idea of existence: libraries exist throughout the world.

English might also say:

• Libraries exist throughout the world
• Libraries are found throughout the world

But bibliotekoj estas tra la mondo would sound odd, because esti is usually for identity, description, location with the right structure, etc., not for the idea of existing in many places.

Because Esperanto does not need a dummy subject like English there.

English says:

• There are libraries...

But Esperanto usually just says:

• Bibliotekoj ekzistas...

This directly means Libraries exist..., which is a very natural Esperanto structure.

Tra means through, across, or throughout, while en means in.

So:

• en la mondo = in the world
• tra la mondo = throughout the world / across the world

In this sentence, tra la mondo emphasizes that libraries exist in many places all over the world, not just that they are somehow inside the world.

La is the definite article, meaning the.

So:

• la mondo = the world

In Esperanto, la is used when the noun is definite, just like English the. Here, we mean the specific world we all know, so la mondo is natural.

You would not normally say just tra mondo here.

The -n ending usually marks the direct object, and sometimes direction.

In this sentence:

• bibliotekoj is the subject
• ekzistas is the verb
• tra la mondo is a prepositional phrase

There is no direct object, so no accusative -n is needed.

Also, after a preposition like tra, you normally do not add -n unless there is some special reason. So tra la mondo is correct as it is.

Yes, Esperanto word order is fairly flexible, because endings show the grammatical roles clearly.

The normal order here is:

• Bibliotekoj ekzistas tra la mondo.

But you could also say:

• Tra la mondo ekzistas bibliotekoj.

That would put more emphasis on throughout the world.

Both are understandable, but the original version is the most straightforward and neutral.

A helpful rough guide is:

bee-blee-oh-teh-KOY ehk-ZEE-stahs trah lah MON-doh

A few useful pronunciation points:

• Stress is always on the second-to-last syllable:
  • bibliotEkoj
  • ekzIstas
  • mOndo
• j sounds like English y
• tra is pronounced with a clear a, not like English tray

Esperanto pronunciation is very regular, so once you know the letter sounds, you can usually read words correctly.

The singular would be:

Biblioteko ekzistas tra la mondo.

Grammatically, that means A library exists throughout the world, which is usually not the intended meaning.

If you wanted The library exists..., you would say:

La biblioteko ekzistas...

But for the general statement about many libraries, the plural bibliotekoj is the right choice.

Yes. Esperanto words are often built from roots and endings.

• bibliotek- = the word root
• -o = noun ending
• -j = plural ending

So:

• biblioteko = library
• bibliotekoj = libraries

Even when a root comes originally from an international word, Esperanto still treats it regularly. That regularity is one of the language’s biggest advantages for learners.