La katido ricevis vakcinon.

Because -id- is a suffix meaning offspring or young one.

• kato = cat
• katido = kitten

So katido is specifically a young cat, not just any cat.

La is the Esperanto definite article, meaning the.

So:

• la katido = the kitten

Esperanto has only one definite article, la, and it does not change for gender, number, or case in this sentence.

In Esperanto, -is marks the past tense.

So:

• ricevas = receives / is receiving
• ricevis = received
• ricevos = will receive

The verb base here is ricev-, meaning receive, and -is tells you the action happened in the past.

The -n ending marks the direct object in Esperanto.

In this sentence, the kitten is the one that received something, and the thing received is a vaccine/vaccination, so vakcinon is the direct object.

• vakcino = a vaccine
• vakcinon = a vaccine, as the direct object

This is one of the most important Esperanto endings to learn.

Because katido is the subject, not the direct object.

In La katido ricevis vakcinon:

• La katido = the subject, the one doing/experiencing the action
• vakcinon = the direct object, the thing received

Only the direct object gets -n here.

Because Esperanto uses la only for the. It does not have a separate word for a/an.

So:

• la katido = the kitten
• vakcinon = a vaccine / vaccination depending on context

If you leave off la, the noun is often understood as indefinite.

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

For example, these mean essentially the same thing:

• La katido ricevis vakcinon.
• Vakcinon ricevis la katido.

Because vakcinon has -n, you still know it is the object.

That said, La katido ricevis vakcinon is the most neutral and natural order.

Ricevis is perfectly natural and means received.

However, depending on context, Esperanto might also use other expressions, such as one meaning was vaccinated. The sentence here focuses on the idea that the kitten received a vaccine.

So this is normal Esperanto, even if another phrasing could also be possible in real life.

A rough guide:

• katido ≈ kah-TEE-doh
• ricevis ≈ ree-TSEH-vees
• vakcinon ≈ vahk-TSEE-nohn

A few useful pronunciation points:

• c is always like ts
• vowels are pure and steady
• stress is usually on the second-to-last syllable

So:

• ka-TI-do
• ri-CE-vis
• vak-CI-non

No. Katido does not specify gender.

By default, Esperanto nouns like this are not marked for male or female unless you add something to show it. So katido simply means kitten.