In English, we would say "The youth are cheerful." It is very uncommon to refer to a single person as "a/the youth." It seems very unnatural to me, is this acceptable in Polish? If so, perhaps the translation of "youth" is incorrect?
Your version works.
A lot of nouns depicting groups of people are singular in Polish. Plural wouldn't work grammatically here, you'd need to change the subject for example to "młodzi ludzie" = "young people".
It does not matter what the Polish is, the English has to work as English. The fact that the Polish is singular must be apparent from the way the material is presented, not by twisting the English into a place it should not go.
That comment is more than 2 years old. "The youth are cheerful" is the main English answer now. For at least a year, from what I see.
well I clicked on the word and then listened to it and there it sounded ok, but here I just hear "di" instead of "dzi"
Yes, @LICA98 you're right. At the top of this discussion page, it does sound like a palatalized D (дь) which I don't even think exists in Polish. - młodiesz.
But when you click only the word młodzież, then it sounds correct with a dź
I typed "The young man is cheerful" and it wasn't accepted. Does the Polish sentence refer to "young people" as a class, or could it refer to one individual (in which case my translation is correct)?
I put 'youths are cheerful' as where I am from, we would never say youth. It just wouldn't make sense here.