Introduction

English language learners (ELLs) are a rapidly growing population in the United States, accounting for 9.1 % or 4.4 million students in public K-12 schools (National Center for Educational Statistics, 2015). By the year 2025, ELLs are predicted to make up 25 % of the student population (National Education Association [NCES], 2005), with the largest number of these students found in California, Florida, Illinois, New Mexico, New York, Puerto Rico, and Texas. However, significant changes in the student population have already occurred in many states, with Arkansas, Alabama, Colorado, Delaware, Georgia, Indiana, Kentucky, Nebraska, North Carolina, South Carolina, Tennessee, Vermont, and Virginia experiencing more than 200 % growth in the numbers of ELLs in schools (NCES, 2015).