Nearly all Dual Language Instruction (DLI) programs share the same three goals that students: 1) develop full bilingualism and biliteracy, 2) achieve academic success at or above grade level in both languages, and 3) develop multicultural competencies (Christian, Howard, & Loeb, 2000; Collier & Thomas, 2004, 2002; Fits, 2006; Freeman, 1998; Lindolm-Leary et al., 2007; Montone & Loeb, 2000). Models can differ in the percentage of time allotted to each language, but are still considered dual language if content is taught in a language other than English (LOTE) for at least 50% of instruction.
Beyond language of instruction time, DLI programs also can differ in the linguistic make-up of their participants. In order to be listed on the Center for Applied Linguistics’s directory of Two-Way Immersion (TWI) programs there must be a balance of language minority and language majority students, with each group making up between one-third and two-thirds of the total program population, while also ensuring that these two groups are integrated for at least 60% of instructional time at all grade levels (Center for Applied Linguistics, 2012). The label Two-Way Immersion comes from the integral structure of the program that first language (L1) English speaking students learn from first language (L1) Spanish speaking (my example) students and vice versa. These programs have by far shown to be the most effective for English Language Learners (ELLs) in not only acquiring English at a faster rate, but also for allowing them to keep developing proficiency in their L1, for a continued link to their home culture and linguistic identity, and also for grade-level (or greater) academic achievement (Thomas & Collier, 2004). L1 English speaking students in these programs also have shown to achieve high levels of academic, second language, and multicultural competency proficiencies.
One-Way Immersion programs are typically implemented in school districts where there is an emphasis on native-English speaking students learning a foreign language. This does not necessarily mean that there is no cultural or linguistic diversity among the students in a One-Way Immersion program, but there is no programatic component of an equal balance between L1 English and L1 Spanish (my example) speakers at all grade levels; as the focus is on a One-Way trajectory from English to a foreign language. The same Dual Language Instruction goals of bilingual & biliterate development, grade level (or greater) academic achievement, and the development of multicultural competencies are closely adhered to in One-Way Immersion programs.
No matter what label is given to a Dual Language Instruction program (Two-Way or One-Way), its potential for success will be centered in how it is implemented (De Jong, 2002) and in the support it receives from students, teachers, administrators, parents, and other community members.
Center for Applied Linguistics. (2012). Growth of two-way immersion programs in the US, 1962-Present. Retrieved November 8, 2012, from http://www.cal.org/twi/directory/
Christian, D., Howard, E. R., & Loeb, M. (2000): Bilingualism for All: Two-Way Immersion Education in the United States, Theory Into Practice, 39:4, 258-266
Collier, V. P., & Thomas, W. P. (2004). The astounding effectiveness of dual language education for all. NABE Journal of Research and practice, 2(1), 1-20.
De Jong, E. J. (2002). Effective bilingual education: From theory to academic achievement in a two-way bilingual program. Bilingual Research Journal, 26(1), 65-84.
Fitts, S. (2006). Reconstructing the status quo: Linguistic interaction in a dual-language school. Bilingual Research Journal, 30(2), 337-365.
Freeman, R. D. (1998). Bilingual education and social change (Vol. 14). Channel View Books.
Lindholm-Leary, K. J., Hardman, L., & Meyer, P. (2007). What makes two-way programs successful at the elementary and middle school levels. Language Magazine. Journal of Communication and Education, 6(5), 10-23.
Montone, C., & Loeb, M. (2000). Implementing two-way immersion programs in secondary schools. Washington, DC, and Santa Cruz, CA: Center for Research on Education, Diversity, and Excellence