Book excerpt: The revised PreK-12 English Language Proficiency Standards build on the World-Class Instructional Design and Assessments (WIDA) Consortium's English Language Proficiency Standards for English Language Learners in Kindergarten through Grade 12 (Wisconsin, 2004). The WIDA Consortium is a group of ten states, formed in 2002 with federal monies, that has developed comprehensive English language proficiency standards. This volume also uses grade-level clusters that reflect current educational configurations in the United States. Each of the five language proficiency standards is divided into the four language domains of listening, speaking, reading and writing. The five levels of language proficiency reflect characteristics of language performance at each developmental stage and include: starting (L1), emerging (L2), developing (L3), expanding (L4), and bridging (L5).