This report on language testing research focuses on lessons applied to limited English proficient (LEP) students and programs. First, a review of the history of primary and non-primary language testing is provided. The question of why there is no field of primary language testing is then discussed. The second major section of the report is a review of the broader literature of educational measurement as it relates to the critical role of language proficiency. The third section offers an idea of the place of language proficiency in a broader theory of human intelligence and representational capacities. Building on findings in non-primary language research, a possible resolution of the apparent controversy over the old notion of a single unifying general intelligence and distinct multiple intelligences is proposed. To conclude, a few observations about how to go about testing the increasing number of LEP students in schools are presented. Deep surface rather than surface assessment through discourse-based, real-life performances are recommended. Two responses to the paper, one by Fred Davidson and the other by Myriam Met, are appended. (VWL)