Lots of Chinese-American children take Chinese language classes starting from kindergarten at Chinese school, which may prepare them for AP Chinese before 9th grade.
Bwahaha. Many of my first-year Chinese classmates in college had a long history of Saturday school. "Oh, that's what my mom's always saying to me!" was a common comment.
I'd guess the very young kids taking the AP Chinese test are native speakers, as opposed to kids of Chinese ancestry for whom English is their first language, Chinese school or no. 73% of overall exam takers get a 5; among kids who aren't native speakers it's 33%.
The Chinese listening SAT Subject exam is even worse. The mean score is a 764, and a perfect 800 is 57th percentile.
