You all must read this fantastic story by Pat Wingert on the challenges schools face in helping ELL students meet the demands of the Common Core standards.
It's not just about raising the rigor (which IS one challenge!), it's also about the standards' emphasis on language and vocabulary -- even in math class.
The new standards also require students to explain in writing how they got their answer, and that requires a broader and more sophisticated vocabulary than many English learners have. “If they don’t have the words, it’s hard to read and listen and speak and write,” Chavarin said. “Vocabulary is the pillar to all of this.”