This is a great study that shows that offering children education in their two languages (in this case Spanish and English) is as effective, if not more effective at helping them achieve “native speaker” results in English language testing. Yes, that’s right – bilingual education does not mean poor English skills and better Spanish skills. It means better Spanish skills as equal or better English skills! Educators, read this and take it to your admin, to promote the support for mother tongue/L1 support in schools!
San Francisco's Bilingual Programs as Effective as English Only, Study Finds – Learning the Language – Education Week.