Li retiris du monbiletojn.

Because it has two different endings added to the noun stem:

• -o = noun
• -j = plural
• -n = accusative, which usually marks the direct object

So:

• monbileto = a banknote
• monbiletoj = banknotes
• monbiletojn = banknotes as the direct object

In Li retiris du monbiletojn, the banknotes are what he withdrew, so Esperanto marks them with -n.

Esperanto often marks the direct object explicitly with -n. English usually relies on word order instead.

Compare:

• Li retiris du monbiletojn. = He withdrew two banknotes.
• Du monbiletojn retiris li. = literally, Two banknotes withdrew he, but still understood as He withdrew two banknotes because -n shows what the object is.

So the -n gives Esperanto more freedom in word order.

Retiris is the past tense form of the verb retiri.

Breakdown:

• re- = back, again
• tir = pull, draw
• -i = infinitive
• -is = past tense

So retiri literally has the idea of pull back / draw back / withdraw, and retiris means withdrew / pulled out / took out, depending on context.

Because ordinary numerals in Esperanto do not take plural or accusative endings in normal use.

So you say:

• du monbiletoj
• du monbiletojn

but du itself stays du.

The noun after the number still shows whatever grammar it needs, so here monbiletojn is plural and accusative.

Esperanto does not use an indefinite article like English a/an at all.

It does have a definite article, la, but you only use it when you specifically mean the.

So:

• du monbiletoj = two banknotes
• la du monbiletoj = the two banknotes

In this sentence, du monbiletojn is perfectly natural without any article.

Yes. Monbileto is a compound:

• mono = money
• bileto = ticket, note, slip
• monbileto = banknote / bill

Compounds are very common in Esperanto. Usually the main idea comes at the end, so this is literally something like a money-note.

Because li is the subject, not the object.

In Esperanto:

• li = he
• lin = him

So:

• Li retiris du monbiletojn. = He withdrew two banknotes.
• Ŝi vidis lin. = She saw him.

Only the direct object normally gets -n, not the subject.

Yes. Esperanto word order is fairly flexible because the -n ending helps show the role of the object.

These are possible:

• Li retiris du monbiletojn.
• Du monbiletojn li retiris.
• Retiris li du monbiletojn.

The first is the most neutral and natural for beginners. Other orders may change emphasis or style.

You would say:

Li retiris unu monbileton.

Changes:

• du → unu
• monbiletojn → monbileton

Why monbileton?

• singular, so no -j
• still a direct object, so it keeps -n

Not always. The exact English translation depends on context.

Retiri can suggest ideas like:

• withdraw
• pull back
• take out
• remove

So Li retiris du monbiletojn could mean something like:

• He withdrew two banknotes.
• He took out two banknotes.

If the context is a bank machine or a bank account, withdrew is probably the best English choice. If he physically pulled notes from a pocket or envelope, took out might sound more natural.

Roughly like mon-bee-LEH-toyn, with the stress on the second-to-last syllable:

mon-bi-LE-toyn

A few helpful points:

• Esperanto stress is almost always on the second-to-last syllable
• j sounds like English y
• oj sounds roughly like oy
• e is like eh

So monbiletojn ends with a sound similar to toyn, but beginning with t: -toyn.