As Congress considers two bills to support Native American language immersion, including the Native Language Immersion Student Achievement Act, it is time to take stock. What does research say about the impact of Native-language immersion on Native students’ academic achievement? We now have 30 years—more than a generation—of data on Native-language immersion in the U.S. and beyond.

But first, what do we mean by Native-language immersion? It may be easier to begin with what immersion is not. Native-language immersion is not simply “Native language instruction.” It is not a pullout program or a 50-minute class. Native-language immersion is not submersion, a method that compels students to learn a second language at the expense of their mother tongue.

Native-language immersion is voluntary; parents often participate in immersion themselves to support their children’s language learning at home. Native-language immersion is additive, building on students’ first-language abilities as a foundation for learning the Native language as a second language. Native-language immersion is full-day or most-of-the-day teaching and learning in the Native language, often complemented by after-school and summer programs. Native-language immersion systematically incorporates Native cultural content and culturally appropriate ways of teaching and learning. Most important, Native-language immersion not only engages students in learning the Native language, but also math, science, social studies, music, art, and even English through that language. In other words, Native-language immersion is a whole program that cultivates what language researcher Fred Genessee calls “the whole child, the whole curriculum, the whole community.”

Hawaiian language immersion provides the most dramatic example of the success of such a program. From a situation in the early 1980s in which fewer than 50 children spoke Hawaiian, Hawaiian-medium schooling has produced 4,000 children assessed as fluent speakers of Hawaiian. These changes have come in tandem with impressive academic gains for historically underserved Native Hawaiian students. In a 2012 issue of the Journal of American Indian Education (JAIE), Professor William Wilson of the University of Hawai‘i Hilo reports on the P-12 Nāwahīokalaniʻōpuʻu (Nāwahī) School, which boasts a 100 percent high school graduation and 80 percent college attendance rate. Although English is not introduced until grade 5, Nāwahī produces graduates who are college-, career-, and civic life-ready for English-dominant settings.

On the Navajo Nation, the Window Rock Unified School District (WRUSD) has run a voluntary Navajo immersion program since 1986. Reporting on the program’s first 10 years, Agnes and Wayne Holm note that immersion students performed as well on local tests of English as their non-immersion peers, and better in English writing and math. Now a whole-school program called Tséhootsooí Diné Bi’ólta’, immersion in WRUSD continues to demonstrate student achievement outcomes equivalent or better than those of English-medium schools serving Navajo students.

Between 2009 and 2011, I conducted a study of Navajo immersion at the K-5 Puente de Hózhó (Bridge of Beauty or PdH) Public Magnet School in Flagstaff, Arizona. Part of the national Promising Practices study led by Professor Bryan Brayboy of Arizona State University, the PdH study responded to Executive Order 13336’s call for research on the role of Native languages and cultures in American Indian/Alaska Native student achievement. On state-required tests, PdH students equaled or surpassed their Native peers in English mainstream schools. In recent years, PdH has ranked among the district’s top-performing schools. Equally important, the study showed that Navajo immersion brought parents and elders into the program, reinforcing intergenerational ties.      

These are but a few examples of Native-language immersion programs demonstrating success:

Akwesasne (Mohawk) Freedom School in upstate New York

Ayaprun Elitnaurvik Yup’ik Immersion School in Bethel, Alaska

Cherokee Immersion Charter School in Tahlequah, Oklahoma

Cuts Wood (Blackfeet) Academy in Browning, Montana

Native American Community Academy (Lakota, Navajo, Tiwa) in Albuquerque, New Mexico

Waadookodaading (Ojibwe) Language Immersion School in Hayward, Wisconsin

While individual program data are informative, equally revelatory are national data. In a 2005 government-commissioned study of best practices in immersion schooling in New Zealand, Professor Stephen May and his associates at the University of Waikato found that Māori-medium programs in which 81 to 100 percent of instruction took place in Māori—called Level 1 programs—produced the strongest academic gains. The researchers attributed this to the well established “language interdependence principle”: The stronger a child becomes in Māori, the more likely s/he is to be successful in English. This also means that immersion requires several years to demonstrate optimal results; students who participated in Level 1 immersion for 6 to 8 years reaped the greatest linguistic, cognitive, cultural, and academic benefits.

In the Promising Practices study, we found that strong Native language and culture programs (equivalent to Māori Level 1) produced the greatest academic benefits, and benefits were cumulative. Therefore, programs need to be long-term. Long-term programs that begin with 90 to 100 percent of instructional time in the Native language and provide high-quality English instruction by the end of the program promote high levels of language acquisition and academic achievement.

Overall, what do three decades of research show? Close examination of the data confirms the benefits of well-implemented immersion in promoting students’ language acquisition, enhanced test performance, increased school retention and graduation rates, college entry, and more diffuse but important outcomes such as parent involvement and cultural pride.

These are not the only goals of these programs, of course, as they are rooted in Native peoples’ inherent and constitutionally and internationally recognized rights to sovereignty and self-determination. Further, Native-language immersion is a positive influence on diversity and equity in schools and society. More research is needed, but the evidence to date strongly indicates that Native-language immersion significantly benefits Native students.

Children get one chance at their P-12 education, and it serves them for life. They deserve the opportunities and academic benefits that Native-language immersion provides.

Teresa L. McCarty is the G.F. Kneller Chair in Education and Anthropology at the University of California, Los Angeles, and the Alice Wiley Snell Professor Emerita of Education Policy Studies at Arizona State University. She is a fellow of the American Educational Research Association and the International Language Revitalization Center. Her recent books include Language Planning and Policy in Native America: History, Research, Praxis (Multilingual Matters, 2013).