This guidebook is intended to assist the classroom teacher in developing assessments for English language learners (ELLs). More specifically, it will: help the teacher to determine whether a student may be an ELL; measure native-language proficiency or the English language proficiency of an ELL; determine initial instructional placement for an ELL in mathematics or reading; measure the academic achievement of an ELL in their native language or in the English language; and provide information on the development of databases to be used in monitoring student performance on the assessments administered. This guidebook is intended for classroom teachers who are currently challenged in determining criteria to be included in the development of performance-based assessments for their ELLs. The responsibility of developing the tasks is that of the teacher. The book includes various checklists, scoring rubrics, sample performance-based tasks, and scoring sheets. In addition to an extensive bibliography and a comprehensive guide to resources and assistance centers in the Northwest United States, there are three appendices: a reader's own scoring guide; a six-trait analytical writing assessment model; and an E.A.R.--a conceptual framework for the traits of competent oral communication. (Contains 53 references.) (KFT)