چكيده
Word knowledge plays an essential role in determining the success of EFL and ESL learners in EAP setting. It is determinant in speaking, reading, writing and listening (Adolphs and Schmitt, 2003). This study aimed at investigating the effects of reading academic essays extensively on incidental vocabulary learning and retention of words from Academic Word List (Coxhead, 2000), and also to evaluate the success of the used material. To this end, 40 pre-university and university students were chosen to take part in the experiment. After administering a pre-test during 17 sessions of experiment, experimental group received 15 first class academic essays, while the control group equally received 15 IELTS model essays written for academic module. Neither groups received instruction of the target words. At the end of the experiment, both groups were given a vocabulary test, to investigate the effect of reading academic essays on their vocabulary learning and retention. Then, their pre and post-test scores were compared using a dependent t -test. The result of the t-test for vocabulary test (t= -8.39, p= .001) showed that experimental group’s vocabulary knowledge had improved significantly in post-test compared to pre-test. Also both groups were administered a delayed post-test the result of which showed that besides having a positive effect on vocabulary knowledge, academic essays effected experimental group’s short-term and long-term vocabulary retention positively while no such result was achieved by the control group. Also, the findings of this study offers that up to 11% of each academic essay is approximately comprised of words from AWL and, if used as supplementary reading material beside textbooks, can help students to improve their knowledge of academic vocabulary.
