One place where it would be quite a clear difference is in sci-fi and fantasy, for example, where there are many characters who are "personoj" (people/persons) but not "homoj" by virtue of not being human.
"Vizio estas maŝino, ne homo. Afabla persono, sed artefarita"
"Kion celon havas Elfo, Homo, kaj Enano en la Rajdantmarko? Parolu rapide"
Here in the real world, in very many contexts "personoj" and "homoj" can be used interchangeably.
For example, Facebook in Esperanto opts for phrasing such as "42 homoj ŝatas ĉi tion".
Hum. Interesting. I think I've been getting them consistently right which might indicate that there is some sort of unspoken rule here that native English speakers understand instinctively, but that maybe doesn't occur in Russian. Was Tri personoj ludas actually marked as wrong? Or was it just an alternative transalation that it showed?
Russian is Russian, but I can distinguish "people/person" and "humans" in English. But I feel that there are some a bit different rules in Esperanto... No, it wasn't marked wrong, it was an alternative (preferred) answer. Why is "homoj" a true answer? We can't say "three humans play" in English, can we? Thanks for that you are helping me. Sorry for my English!
Good point re: Russian/English. Sorry.
Your certainly right, "three humans play" sounds very strange, though understandable. I'm a bit stuck to be honest. I suppose there are two options.
The homoj/humans and personoj/people translations are not fully accurate - as you said.
There's a slight problem with that Duolingo sentence - an inaccurate answer has got into the system somehow.
Honestly, I don't think I can help. I'm not experience enough to know which answer is right. Hopefully someone else can help.
Hm, if we want to say that somebody/something is somewhere, we should use the phrase with "there is/are". Like German "es gibt" or French "il y a" or Russian "есть".
So, if you want to point to the location of the three people, you should use "there is/are". But although, according to FredCapp, the phrase without "there is" is used in US.
Chambre is also derived from the Latin camera (a variation of camara) meaning a vaulted room. That is ultimately (at least per my dictionary) from the Greek Kamara meaning arched (ceiling). So it turns out that ĉambro and chamber are etymologically related to (the English word) camera. (fotilo)
Sometimes this stuff is really fun.