The most powerful, research-proven program for developing biliteracy, academic excellence, and global citizens.
Dual language education — also called two-way immersion — is a program model where students develop literacy and academic skills in two languages simultaneously. Unlike transitional bilingual programs that phase out the home language, or ESL pull-out models that isolate English learners, dual language fully develops both languages.
The program serves both native English speakers and native speakers of another language (most commonly Spanish) in the same classroom, with the goal that all students become biliterate and bicultural by the end of elementary school.
Every strong dual language program is built on these five foundations.
Students develop full literacy in both languages — reading, writing, speaking, and listening. They are not learning half of each language; they are becoming fully literate in two. This is the most powerful academic gift a school can give.
Content — math, science, social studies — is taught in both languages. Students build deep conceptual knowledge that transfers across languages. By 5th grade, dual language students consistently score 15–20 percentile points higher than peers in monolingual programs.
Students learn to navigate and appreciate multiple cultures. They develop empathy, global awareness, and the ability to build bridges across communities. In a diverse world, this is not a bonus — it is a survival skill.
Knowing two languages gives students a unique window into how language itself works. They understand grammar, sentence structure, and word patterns more deeply than monolingual peers — a skill that boosts reading comprehension in both languages.
Dual language adds a new language without subtracting the home language. This stands in direct contrast to subtractive models where students lose their heritage language while learning English. Preserving the home language preserves identity, family connection, and community.
“After 5 years in a dual language program, students outperform comparison students in both reading and math — in both languages — with the advantage growing larger every year.”
— Thomas & Collier, 2012 — 30-year longitudinal study
“Dual language education is the only program model that has been shown to close the achievement gap for English Language Learners over time.”
— Howard, Sugarman & Christian — Center for Applied Linguistics
“The cognitive advantages of bilingualism — including better attention, task-switching, and working memory — are not side effects. They are the result of the constant mental exercise of managing two languages.”
— Dr. Ellen Bialystok — York University
These evidence-based strategies make dual language programs work in real classrooms.
In the 90/10 model, instruction begins with 90% in the target language and 10% in English, gradually shifting to 50/50 by upper grades. In 70/30, the split starts at 70% target language. Both models produce stronger biliteracy than programs that try to teach both languages equally from Day 1.
Languages are kept separate by teacher, time of day, or physical space — never mixed in a single lesson. This prevents language mixing (code-switching as a crutch) and pushes students to develop full proficiency in each language independently.
A key concept is introduced briefly in Language A (preview), taught fully in Language B, then reviewed again in Language A. This bridges comprehension gaps without compromising the language separation principle.
English and Spanish share over 10,000 cognates — words that look and mean the same thing (information / información, family / familia). Teaching students to recognize and use cognates dramatically accelerates vocabulary growth in both languages.
Skills learned in one language transfer to the other. A student who masters phonemic awareness in Spanish carries that skill into English reading. Teachers intentionally leverage these transfers to accelerate literacy in both languages simultaneously.
Read our blog for practical insights, or explore how the Science of Reading pairs with dual language.