As a high school pupil, my cousin felt very sorry for her French teacher. She told me that
most of the class were disintersted in studying a foreign language.

That's because they are forced to; there's no incentive to learn.
I remember going on a school trip to Italy when I was 14. Our Latin teacher spoke Italian and offered to give up his lunch break in order to teach students some basic Italian. In two weeks I learnt more Italian that I learnt French in 5 years!

Yes, I agree with your comment about the gaokao favouring all-rounders. However, it puts heaps of pressure on students. They are all required to be good at everything, and that's a huge ask!