English language learners (ELLs) were once expected to learn English before they learned critical content needed to succeed in school, but this is longer true, because now federal education laws require that ELLs be held to the same academic standards as other students. There are, however, requirements to assess and document progress on tests of English language development. This study sought to provide information on the links between academic language, language proficiency tests, and performance on standardized assessments by examining relationships among: (1) two language proficiency measures (e.g., Language Assessment Scale (LAS) and Minnesota's Test of Emerging Academic English (TEAE); (2) teacher ratings of classroom reading and writing samples; and (3) two state achievement tests: Minnesota's Comprehensive Assessments (MCAs) and Minnesota's Basic Skills Test (BSTs). The goal was to describe the role that academic language might play in determining differences among language proficiency tests. The researchers sampled 99 English language learners (ELLs) in grades 3, 5, and 11. In examining the relationship between the LAS and TEAE in this sample of students, the researchers found that the underlying reading skills being measured by the two tests were closely related. indicating that the students who performed one way on one test tended to perform a certain way on the other test. The writing tests for the LAS and TEAE were not related, indicating that the tests are either measuring different skills, or are measuring underlying skills differently. Teachers who were licensed to teach English as a Second Language (ESL) tended to rate students' skills as either the same or higher than the students' content teachers. Both ESL and content teachers tended to rate listening and speaking skills higher than students' skills in reading or writing. Teacher opinions about specific students' chances to succeed in future classes without further language support were related to whether students had achieved passing scores on the Basic Skills Tests and had at least been rated as "achieved" on the Minnesota Comprehensive Assessments. Although certain Language Assessment Scales scores (reading and overall) were significantly correlated with the MCA writing test and BST reading test, there appeared to be stronger correlations between the TEAE reading score and the MCA and BST reading scores. Comparisons of ESL and content teacher ratings of student ability with scores on state achievement tests showed inconsistencies based on whether the teacher was an ESL or content teacher. The comparisons of proficiency test data and state test data showed that certain language proficiency scores (reading and overall) were significantly correlated to the MCA writing test and BST reading test. However, stronger correlations were observed between the TEAE reading score and the MCA and BST reading scores. In comparing student performance on state tests with teacher ratings on a question about students' ability to succeed without further language support, most of the students rated as likely to succeed had achieved passing scores on the BST and had at least been rated as "achieved" on the MCA tests. (Contains 44 tables.)