La vilaĝo havas bankejon.

Because it is the direct object of havas.

In Esperanto, the thing that is directly had, seen, made, etc. often takes the accusative ending -n.

• La vilaĝo havas bankejo would be incorrect here.
• La vilaĝo havas bankejon is correct because the village has the bank.

So the pattern is:

• vilaĝo = village
• havas = has
• bankejon = a bank / bank building, as the object

The suffix -ej- means place for or place associated with something.

So:

• bank- = bank
• -ej- = place
• -o = noun ending

That gives bankejo, literally something like a banking place.

This suffix is very common in Esperanto. For example:

• lernejo = school, literally learning place
• kuirejo = kitchen, literally cooking place
• vendejo = shop/store, literally selling place

So bankejo emphasizes the physical place where banking happens.

Often, yes.

Banko is the ordinary word for bank in many contexts, and many speakers would probably use bankon naturally in a sentence like this.

Using bankejon is still understandable and grammatical, but it can sound like you are emphasizing the place/premises/branch rather than just the institution.

So the difference is roughly:

• bankon = a bank
• bankejon = a bank building / banking place

In everyday use, bankon may be more common, but bankejon clearly shows how -ej- works.

La is the Esperanto definite article, meaning the.

So la vilaĝo means the village.

It is used when the village is specific or already known from the context. That is very similar to English the village.

Unlike English, Esperanto has only one article:

• la = the

It does not change for gender, number, or case, although if needed the -n may appear in special situations such as direction, not here.

Because Esperanto has no indefinite article.

English distinguishes:

• the bank
• a bank

Esperanto only has la for the. If there is no article, that can correspond to English a/an or sometimes just a bare noun, depending on context.

So:

• banko or bankejo can mean a bank
• la banko or la bankejo means the bank

That is why bankejon has no extra word before it.

The ending -as marks the present tense in Esperanto.

So havas means has or have, depending on the subject.

Here the subject is la vilaĝo, which is singular, so in English we translate it as has.

A useful point for English speakers: Esperanto verbs do not change form for different persons.

• mi havas = I have
• vi havas = you have
• li havas = he has
• la vilaĝo havas = the village has

The verb stays havas in all those examples.

Not completely, but La vilaĝo havas bankejon is the most neutral and natural order.

Esperanto word order is more flexible than English because the -n ending helps show what the direct object is. So other orders are possible, such as:

• Bankejon havas la vilaĝo

That is still understandable because bankejon has -n, so you can tell it is the object.

Even so, learners should usually start with the standard subject–verb–object order:

• La vilaĝo = subject
• havas = verb
• bankejon = object

Yes. That would also be a natural way to express the idea.

These two patterns are both possible:

• La vilaĝo havas bankejon = the village has a bank
• En la vilaĝo estas bankejo = in the village there is a bank

The first sounds a bit like talking about what facilities or amenities the village possesses.
The second sounds more like simply stating that a bank exists there.

Both are good Esperanto.

A few important points:

• ĝ sounds like the English j in judge
• stress in Esperanto normally falls on the second-to-last syllable

So:

• vilaĝo is stressed on LA: vi-LA-ĝo
• bankejon is stressed on KEJ: ban-KEJ-on

Very roughly in English-style spelling:

• vilaĝo ≈ vee-LAH-jo
• bankejon ≈ bahn-KAY-on

Also note that Esperanto vowels are pronounced clearly and consistently, not with lots of English-style variation.

This sentence shows several of the most important Esperanto endings:

• -o = noun
  
  • vilaĝo
  • bankejo
• -as = present-tense verb
  
  • havas
• -n = accusative / direct object ending
  
  • bankejon

So this one sentence already contains three very common Esperanto grammar markers. Learning to spot these endings makes Esperanto much easier to read.