• Language Essentials for Teachers of Reading and Spelling (LETRS) is a professional development course required for all PreK through 5th grade teachers, administrators, and coaches. LETRS provides in-depth knowledge based on the most current research regarding what, when and how language skills need to be taught; ways to assess student language development for prevention and intervention; guidance on how to plan and balance word recognition and comprehension instruction; and information on how to differentiate instruction to meet the needs of all students.