When South Koreans hear “defectors,” they usually think of Koreans that speak the same language, albeit with the distinctive North Korean dialect. So when you visit a school for defector children in the South, you might wonder why more than half now speak in Chinese.

“My name is Chun-mi, and in Chinese pronunciation, it’s Chun Mei (春美),” says one student at the Durihana International School, an alternative school for defector children in Seoul.

Chun-mi is the 17-year-old child of Su-jin Joo, who defected from North Korea 23 years ago, and she was born in China.

Out of the roughly 30,000 North