The Council for Exceptional Children (CEC) just publish a great teacher and parent resource on what Response to Intervention (RTI). It compiled the most pressing articles published in the area from explaining RTI to how to refer ELL for special education academic difficulties.
My most recent article in this book titled “English language Learners and Response to Intervention: Referral Considerations” provides guidelines and considerations for referring ELLs to special education with a focus on potential learning disabilities. It provides a RTI model that address progress monitoring for ELLs, a case study exemplifying the process recommended, and a worksheet with questions that guide decision-making on eligibility for special education services or language differences.
or you can acess directly from the Teaching Exceptional Children webpage. Teaching Exceptional Children, Vol. 40(5), pp 6-14.