Teachers spend a lot of time finding 'just right' picture books for their students. However, much of what is known about a book's difficulty level was developed with native English speakers. More needs to be developed with the distinctive characteristics of English Learners (ELs). This study reports on the selection of picture books to teach in an intensive week-long intervention with Spanish-speaking ELs in a low SES community in Panama. It applies the concept of tellability rather than readability. Tellability considers who is speaking about what to whom and in what circumstances. Novice teachers who were not fluent in Spanish learned to successfully select and instruct using carefully selected books for teaching English in science-themed lessons. These teachers considered features of books that matched the ELs' oral and written English abilities as well as matched specific language teaching strategies for EL beginners.