I am working on a presentation: ELL Pedagogical Decisions for School Districts.
Part of the support for my recommendations will come from empirical research in bilingualism. I will update this posting with the sources I am using.
Language and Literacy in Bilingual Children by D. Kimbrough Oller and Rebecca E. Eilers (Eds.) (2002).
For an excellent review of the book see Language and Literacy in Bilingual Children. (Book Review). Erika Hoff. International Journal of Bilingualism 7.1 (March 2003): p101(4)
