La bankkonto havas saldon.

Because saldon is the direct object of havas.

In Esperanto, the thing that receives the action of the verb gets -n. Here:

• La bankkonto = the subject, the thing doing the having
• havas = has
• saldon = the thing being had

So saldo becomes saldon.

The ending -as marks the present tense in Esperanto.

So:

• havas = has / have
• havis = had
• havos = will have

The verb form does not change depending on the subject. So:

• mi havas = I have
• vi havas = you have
• la bankkonto havas = the bank account has

That is much simpler than English, where have changes to has for some subjects.

Because Esperanto commonly forms compound words by joining roots together.

Here:

• banko = bank
• konto = account

Together, bankkonto means bank account.

In compounds, the main idea usually comes at the end. So a bankkonto is a kind of konto related to a banko.

Also, the first part of a compound often appears without its usual -o ending, which is why you get bank-konto, written as bankkonto.

La is the Esperanto word for the.

So La bankkonto means the bank account, referring to a specific account rather than just any account.

A useful thing to know: la never changes form. It stays la no matter whether the noun is singular, plural, subject, or object.

Esperanto has no indefinite article. There is no separate word for a or an.

So a bare noun can mean:

• saldo = a balance / balance

In this sentence, saldon simply means a balance or just balance, depending on how the meaning is being expressed in English.

That is normal Esperanto.

Because the sentence is expressing possession, not identity.

• havas = has
• estas = is / are

So:

• La bankkonto havas saldon = The bank account has a balance.

If you used estas, you would be saying something different, not that the account possesses a balance.

Yes, Esperanto word order is fairly flexible because grammar is shown by endings.

The normal order is:

• La bankkonto havas saldon.

But because saldon has the -n ending, you could move it for emphasis:

• Saldon havas la bankkonto.

That is still understandable, but it is less neutral. For learners, subject + verb + object is the safest and most natural pattern.

Because bankkonto is the subject, not the direct object.

Only the direct object gets -n here.

So:

• La bankkonto = the account, the thing doing the having
• saldon = the balance, the thing being had

If bankkonto were the direct object in another sentence, then it could take -n.

It is a normal and natural Esperanto compound.

Esperanto often builds vocabulary this way, by combining simple roots into a clear compound word. That makes bankkonto easy to understand even if you have never seen it before.

This is one of the strengths of Esperanto: once you know the pieces, many words become guessable.