The ''On'' in the french grammar is called ''le pronom personnel indéfinie'' (indefinite personal pronoun)
On (french)= man (swedish) = you (english)
On doit respecter les personnes âgées
Man måste respectera de äldre //You have to respect the elderly.
The resemblance between the French and Swedish in this example is strong, surprising and authentic while it is the Swedish and English that are supposed to have similarities because they are Germanic languages!!
It's strange to look at the etymology. English can use either you or one interchangeably for this. English one can trace back to Latin, yet only this special usage of it is from French influence. Despite that, French on is actually unrelated and this usage comes from Germanic, like English you!
I don't know about Croatian, but I do know that in very many cases, a Swedish construction with man is well translated into Russian with a passive sentence (not in this specific sentence though), so I think that makes sense.
In comparison with English for this specific sentence, we could both use a passive here with much the same result, eg. I Sverige talas det svenska and Swedish is spoken in Sweden, so English is more similar to Swedish.
It's like: "In my country, you hold the door for a lady; it's just what you do!".
This use of English "you" (Swedish "man") is an indefinite personal pronoun known as "generic you". It's distinct from other uses of "you". Like "one", it refers to anyone (an unspecified individual or group of individuals). No specific person is actually being told to hold doors open for ladies. The listener and speaker may both expect never to actually travel to that country. "it's just what you do there".
You can use both in Spanish, "se" and "uno". "How can you say...?" is: "¿Cómo se dice...?" "¿Cómo uno dice...?" sounds weird. It would be: "¿Cómo dice uno...? But still it can have a different connotation. "En España, se habla español"="In Spain, Spanish is spoken" If you say, "En España, uno habla español", it means something like "that is what you have to speak in Spain". It is not a general information about which language is spoken in Spain but about what you have to do there. A bit... intimidating? Both is also used: "¿Cómo se siente uno después de un viaje?"= "How does one feel after a trip?" Although here "sentirse" is a reflexive verb. :)
I get the impression that 'tala' is like 'speak' (as in, speak a language, speak to an audience, speak clearly), while 'prata' is like talk (as in talk to someone, talk among yourselves). So, if I understand right, you could say 'snälla tala långsamt när du pratar med mig' - 'please speak slowly when you talk with me'.
But I could be wrong.