Apparently, lots of Koreans speak Chinese.
For example,
migrants from China (PRC) make up 56.5% of foreign nationals, but approximately 70% of the Chinese citizens in Korea are
Joseonjok (조선족), PRC citizens of Korean ethnicity.
Almost all South Korean students today learn
Englishthroughout their education, with some optionally choosing Japanese or Mandarin as well.
https://en.m.wikipedia.org/wiki/South_Korea