Translation:Everyone's children participated in the holiday.
I suppose part of learning a language is learning to guess the right word when the one you heard is not a real word.
In Esperanto you are "participating something" which in english is usually said as "participating in something" Thus the party is the direct ocject.
But you can also say "partoprenis en la festo" (probably influenced by english), which case the party is the place where you performed the action rather than the direct object
There are actually several languages that use a preposition similar to "en" to describe participating in or taking part in something.
I would treat Wiktionary entries with caution. Certainly it is wrong here, because "partopreni" can be either transitive or intransitive, according to Plena Ilustrita Vortaro.
This is true. The question is not what Wiktionary says, but how the word is used. I note, however, that PIV does not exactly say that it can be either transitive or intransitive. Rather it says that it can be used with -n or en.
You are right, thanks. But surely unless the -n is there for some other reason, like motion towards, which wouldn't really fit with "partopreni", it signifies that the verb is transitive. But I may have misunderstood what you meant.
Duolingo said I made a typo, but the correct answer duolingo gives looks exactly like what I typed.
exactly the same problem, my answer is letter for letter the same as the correct one, but it is marked as wrong- perhaps a program fault here.
Perhaps you used the wrong apostrophe.
Or you used the correct one and Duo has got the wrong one.
And if you mean the Esperanto translation, I have noticed a space after the full-stop.
Do you mean words like "Ĉies", "kies" and "nenies"? If so they are part of the table of correlatives, which consists of groups of words beginning with i, ti, ki, neni, and ĉi. The es ending refers to possession, so "ies" means "somebody's", "ties" means "that person's", "kies" means "whose" (which person's?), "nenies" means "nobody's" and "ĉies" means "everybody's". You can find a complete table of the correlatives at https://en.wikibooks.org/wiki/Esperanto/Appendix/Table_of_correlatives