Studies conducted across the United States to examine the effectiveness of one-way and two-way immersion programs, such as the research of Thomas and Collier (1995, 2002) and Lindholm-Leary (2005), consistently found that well-designed programs help students develop proficiency and biliteracy in two languages. Research also shows students of both language backgrounds achieve at or above grade level scores on standardized tests. 

For English speakers, research shows:

• English speakers develop proficiency in two languages.
• English speakers develop a positive sense of self, and demonstrate positive cross-cultural attitudes and behaviors.

For non-native English speakers, research has shown:

• English Language Learners (ELLs) who receive native language instruction were able to catch up to or surpass the achievement levels of ELL peers and English-only peers who were educated in English-only mainstream classrooms. These results were found regardless of the student’s socioeconomic background.
• ELLs who participated in programs that provided extended instruction in the native language (i.e. dual language programs) outperformed students who received short-term instruction through their native language (i.e. transitional bilingual education).

"Proficiency in more than one language is a valuable skill to be cultivated and nurtured in our schools and communities. Bilingual education is an umbrella term for many types of programs in which two languages are used for instruction.

Dual Language education is an effective approach to developing language proficiency and literacy in English and a partner language.

Bilingual and Dual Language programs promote bilingualism and biliteracy, grade-level academic achievement and cross-cultural competence in all students. Students maintain their native language while adding another language, and they develop pride in their own culture while developing an understanding of others."