"I do not like the youth."
Translation:Nie lubię młodzieży.
Slight problem here. Apart from the period of somebody's life, "youth" has two meanings, both mainly used in newspapers but not much in conversational English.
"Youth" can refer to all young people in general, in which case it takes a plural verb (at least in BrE):
"The youth of today don't know how lucky they are"
But "youth" (countable) can also refer to a single male teenager/young man, often suspected of being "up to no good":
"Two suspicious looking youths were seen standing on the street corner"
If we say "I don't like the youth", I think most people would understand that we are talking about one young man.
To talk of young people in general, we'd simply say "I don't like young people" (best answer here, I think).
If we use "the" with "youth" in this general meaning, we need to specify which young people:
"I don't like the youth of this town"
And if we use "I do not like youth"? Will it suggest "I do not like that period of one's life"?
We shouldn't rather use "young people" as the default, because then, why isn't "młodych ludzi" the default Polish sentence?
Also, is "youth" often used in the singular meaning? I'm of course only an EFL student, but it seems very strange to me and I've only encountered it recently for the first time (here, on Duolingo).
Hi. As to your first question, no, because we tend to use it with a possessive or "a", when speaking personally:
"I have bad memories of my youth"
"I had a difficult youth"
The most natural solution would be to use "Young people", without "the", as it's young people in general. This is also the translation given in the PWN/Oxford Wielki Słownik (the translator's bible, as far as I'm concerned), which doesn't even mention "youth". According to Longman, in this sense, "youth" is used with "of" something, as in my example above, and other dictionary examples also tend to be with "of".
I can't really comment on the Polish expressions as I don't know in what contexts you'd use one rather than the other.
As for your last question, it's not uncommon, but appears mostly in newspapers, mainly tabloids I think, often, but not always, related to crime:
Baltimore cops arrest and charge nine youths for robbery - (Daily Mail Online) Youths joyride on buses in depot - (Sky News)