The present study examines the role of Gal’perin’s Concept-based Instruction (CBI) as a pedagogical approach in teaching cognitive grammar-based (CG-based) concepts of tense and aspect to EFL students. Following the sociocultural theory of L2 Acquisition (SCT), arming L2 learners with scientific concepts can lead to L2 development by deepening their understanding and raising awareness of L2 structures. To this end, over the course of eight weeks 28 third grade middle school students (14 years old) received the concepts in the CBI framework and 30 third grade middle school students received a traditional type of instruction. There were three sets of data including definition of the concepts of tense and aspect before and after CBI, concept verbalization data during CBI, written discourse performance plus responses to a set of grammatical questions before and after CBI. It was found that although both groups improved significantly after receiving the instruction, the students who received CBI performed significantly better than those in the traditional group. The students who received CBI also produced a significant definition of the concepts and their written discourse performance and responses to the grammatical questions improved after CBI. The result provides insight into the application of scientific concepts in L2 instruction.
