Kiam la etaj infanoj denove komencis ŝerci, eĉ la laca avino ekridis.

Kiam means when and introduces a time clause.

So:

• Kiam la etaj infanoj denove komencis ŝerci = When the little children started joking again

This whole part sets the time for the main action:

• eĉ la laca avino ekridis = even the tired grandmother burst out laughing

In Esperanto, kiam can be used both as a question word (When?) and as a conjunction (when) introducing a subordinate clause.

The comma separates the subordinate time clause from the main clause.

• Kiam la etaj infanoj denove komencis ŝerci, = subordinate clause
• eĉ la laca avino ekridis. = main clause

This is very similar to English:

• When the little children started joking again, even the tired grandmother laughed.

The comma helps show the structure clearly.

Yes. Esperanto allows that easily.

You could also say:

• Eĉ la laca avino ekridis, kiam la etaj infanoj denove komencis ŝerci.

That means the same thing. The original version puts the when-clause first, which is very natural.

La is the definite article, meaning the.

So:

• la etaj infanoj = the little children
• la laca avino = the tired grandmother

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

It is normal to repeat la with each separate noun phrase, just as in English you would say the little children and the tired grandmother.

Because they are plural.

• infano = child
• infanoj = children

Adjectives in Esperanto must agree with the nouns they describe in number and case.

So:

• eta infano = a little child
• etaj infanoj = little children

The -j marks plural on both the noun and the adjective.

Because infanoj is plural, the adjective has to be plural too.

Esperanto adjective agreement is very regular:

• singular noun → singular adjective
  
  • eta infano
• plural noun → plural adjective
  
  • etaj infanoj

This agreement is one of the most important patterns in Esperanto.

Denove means again.

Here it modifies komencis ŝerci:

• denove komencis ŝerci = started joking again

Its position is fairly flexible in Esperanto, though some positions sound more natural than others. In this sentence, putting it before komencis is completely normal.

For example, these are all understandable:

• denove komencis ŝerci
• komencis denove ŝerci
• komencis ŝerci denove

The exact placement can slightly affect emphasis, but the basic meaning stays the same.

This is a very common Esperanto pattern:

• komenci + infinitive

So:

• komencis = began / started
• ŝerci = to joke

Together:

• komencis ŝerci = began to joke / started joking

The verb komencis is the main finite verb, in the past tense, and ŝerci stays in the infinitive form ending in -i.

This is much like English started to joke.

Because -i is the Esperanto infinitive ending, equivalent to English to ....

• ŝerci = to joke
• ridi = to laugh
• komenci = to begin

After a verb like komenci, Esperanto often uses an infinitive:

• Li komencis kuri. = He began to run.
• Ili komencis kanti. = They began to sing.

So komencis ŝerci is exactly the expected form.

Eĉ means even.

In this sentence, it emphasizes la laca avino:

• eĉ la laca avino ekridis = even the tired grandmother burst out laughing

The idea is that if even she laughed, then the children must have been especially amusing.

In Esperanto, eĉ usually comes right before the word or phrase it emphasizes.

Because there is no direct object here.

The main parts are:

• la etaj infanoj = subject of komencis
• la laca avino = subject of ekridis

And:

• ŝerci is an infinitive verb, not an object noun

Since no noun is functioning as a direct object, no accusative -n is needed.

This sentence is a good example of Esperanto without any accusative marking at all.

The prefix ek- often means to start doing something suddenly or to do something briefly at the onset.

So:

• ridis = laughed
• ekridis = started laughing, burst out laughing

In this sentence, ekridis is stronger and more vivid than plain ridis. It suggests a sudden reaction.

That is why ekridis fits well here: the grandmother suddenly broke into laughter when the children started joking again.

A few key points:

• ŝ sounds like English sh
• c sounds like ts
• r is usually rolled or tapped
• stress in Esperanto is always on the second-to-last syllable

So:

• ŝerci ≈ SHER-tsee
  Stress on sher
• ekridis ≈ eh-KREE-dis
  Stress on kri

More broadly:

• kiam ≈ KEE-am
• avino ≈ a-VEE-no
• infanoj ≈ in-fa-NOY

The regular spelling and stress system is one of Esperanto’s easiest features once you get used to it.