Clients in the immersion model practiced at MIIS, for example, are highly motivated, well educated, literate adults, often with college educations, who have self-selected into the situation and the language of study. These students already have well developed proficiency and literacy in their first language. They also have completed their formal education and have both basic general content area knowledge, and specialized knowledge within their areas of specialization. In contrast, California students may be refugees or immigrants with limited schooling in their home country or they may be young children born in the U. S. to parents who are themselves immigrants or refugees. There are many existing successful models for second language acquisition, but none which demonstrate significant achievement after only a year of instruction.
Students progress at various rates.
There are several variables which affect progress, including age, degree of proficiency in the first language, family composition, personality and attitude. Students with limited schooling in the home country have more difficulty with English. Students whose parents are well educated in the home country, and whose parents are bilingual or studying English, do better than students whose parents have limited education and who have no opportunity to study English. These generalizations are supported by research. Two way immersion programs have the goal of bilingualism and biliteracy for their student population, which consists of English language learners and also English speakers.