These are the English Language Proficiency Assessment for the 21st Century (ELPA21) standards. From the introduction: "Building on the ELPD framework, CCSSO has utilized the services of WestEd and the Understanding Language team at Stanford University to develop a new set of ELP Standards which were completed in April 2014. The ELP Standards correspond to the Common Core State Standards (CCSS) and the Next Generation Science Standards, highlighting and amplifying the critical language, knowledge about language, and skills using language in the CCSS necessary for ELLs to become successful in schools. The ELP Standards are designed to facilitate the development of English language proficiency essential to students as they increase competence in the disciplinary (i.e., subject-specific) practices associated with English language arts, mathematics, and science."
This resource is extraordinarily useful for understanding how to support English learners in developing competencies in English. In particular, it helps teachers integrate language development into subject-area content and practices, including ELA, science, and mathematics. This standards document provides many tables and diagrams illustrating the correspondence between, on the one hand, English Language Proficiency Standards and ELA Content Standards, and, on the other, ELA, mathematics, and science practices.