Document Type : Original Research Article
Department of English, Torbat-e-Heydareih Branch, Islamic Azad University, Torbat-e-Heydareih, Iran.
Department of English, Mashhad Branch, Islamic Azad University, Mashhad, Iran.
The nature of language proficiency has been the object of much theoretical discussion and empirical investigation for approximately 60 years. So far, different models of proficiency have been proposed to define language and language ability, either has approached it through a different prospective and meanwhile they have added more complications to the definition. This article is intended to accomplish a historical review of more remarkable models of language proficiency and some of their contributions in developing our understanding of what we, as language assessors, have to measure. Also, the writers try to discuss some of the complications and misunderstandings in these models.