Q: "Youths from a village were to join Japanese students for a study program, but the community was anxious because a previous group of German students had intimidated the villagers with their excellent English and polite inattention. For months before the Japanese came, there was concern about how they would adapt and how the shy local youths would communicate."

Here, what does "polite inattention" mean?
A: basically it means not being too open or nosy to a stranger so you don't annoy them. In this case I would guess the german students didn't interact much with the villagers bc they thought they want to be left alone, even though they were just shy.
Q: Youths are frequenting this shopping mall.

1. Correct usage of ‘youths’?
2. Are youths only boys or girls as well?

Thank you. ☺️
A: This sentence is correct.
Youths mean something like teenagers, and teenagers are both sexes. Well yes, boys and girls.
Q: Youths 🚶🏼 この表現は自然ですか?
A: The "th" is youths should be pronounced the same way as in "the" and "their" and "this" rather than in "thin" and "thought".