Dual Language Learners

Around one in five American students currently speaks a language other than English at home, and Census projections estimate that this number will continue to rise in the coming decades. These multilingual children are commonly known as “dual language learners” (DLLs), since they generally begin learning English while they are still working towards basic proficiency in their home language. The growth in this demographic is most dramatic in the early years—nearly one in three Head Start participants is a DLL.

In the PreK-12 years, federal law requires schools to provide these students with language instructional services. This additional support can take one of two forms: English as a Second Language (ESL) or bilingual programming. Within these two categories, there is a large variety of model types. In recent years, a growing body of research suggests that instructional models that incorporate a DLL’s home language leads to higher academic achievement than English-only approaches. Several state and district leaders have also pushed to ensure that all mainstream teachers—in addition to DLL specialists—use best practices to support DLLs in their classrooms.

Beyond instructional considerations, part of the challenge in better serving DLLs lies in appropriately identifying, assessing and exiting them from services when they reach English proficiency. In particular, it can be difficult to develop fair, valid testing and accountability policies since many factors influence the unique developmental trajectory a DLL takes to acquire English. Moreover, there is large variability in how states track their DLLs’ English language and academic progress due to differences in assessments, cut scores and data reporting. This leads to a lack of clarity on how DLLs are performing over time and across state lines.

Key Definitions

A number of terms are commonly used in research, legislation, and other writing to discuss students who speak a language other than English at home. Understanding the differences between these key terms is important for determining which population of students is being discussed.


Children between the ages of zero and eight years old are the most diverse age group in the United States. Compared to other age groups, they are more likely to be racial and/or ethnic minorities, be born to immigrant parents, and speak a language other than English.


Federal language education legislation has only come about in the last 50 years and has largely focused on teaching English to non-English speaking students. While federal initiatives have largely broadened instructional options for ELLs, some states have responded with their own English-only laws.


DLL Assessment

The Every Student Succeeds Act (ESSA), the most recent reauthorization of the Elementary and Secondary Education Act of 1965 (ESEA), requires that states test students annually in English Language Arts and Math in grades 3–8 and once in grades 10–12.



Today when a student enters public school for the first time in the United States, be it in kindergarten or at a point during high school, his or her need for English language services is evaluated.


Instructional Models for DLLs

One of the most important school factors impacting dual language learners’ (DLLs) English acquisition is the educational model through which they are instructed. The ways DLLs are taught also impact their native language skills and content knowledge.