"90/10: This “full immersion” program is found in two-way and developmental bilingual programs and the minority language is used most or all of the day in the primary grades (80-90%). Foreign-language (one-way) immersion programs that implement the full immersion program often use the minority language for 100% of subject matter instruction. Percentage of non-English instruction decreases annually until both English and the target language are used equally"

http://paassc.com/2015/11/10/two-way-immersion-programs/

: Standards and Objectives of ELL Programs