The present paper attempts to provide a critical evaluation of the most prominent pedagogical models that have dealt with the language of the second language (L2) learner starting from the second half of the 20th century. The three most influential approaches in the domain are investigated in this study: contrastive analysis (CA), error analysis (EA), and interlanguage (IL). Each of these models is tackled in terms of its beginning, psychological background, essential tenets, mechanism, and its pedagogical value. Prominently, this work is aimed at teasing apart the confusion that surrounds the fields of acquiring second/foreign language. It also endeavors to clear out the overlapping of both terminology and concept that cloud these areas. Focus is placed on IL owing to the dominant share of attention it has received from researchers and applied linguists who have found many of their questions answered and many information-gaps filled in with this theory. This review paper is an extract of an in-progress PhD dissertation on interlanguage pragmatics of Kurdish university EFL learners, which is an applied study addressing both the pragmalinguistic and sociopragmatic knowledge of the students.