From Stanford University:

Two studies show immersion students achieve proficiency in Mandarin without falling behind in other subjects.

Stanford Graduate School of Education researchers found that 4th and 5th graders in a Palo Alto, Calif., Mandarin immersion program attained a level of linguistic competency comparable with that of nearby high schoolers completing the 4th and 5th level Advanced Placement Mandarin courses.

Some of those Ohlone Elementary School immersion students even outperformed the teenagers in reading. Perhaps most startling, there was little difference in achievement between the heritage learners at Ohlone and their classmates who had no previous exposure to Mandarin.

HWIS has found similar results in our students.

 

Read more:

https://ed.stanford.edu/news/why-palo-alto-grade-schoolers-read-mandarin-better-students-ap-chinese-classes