Defossilization of Fossilized Pragmatic Routines: Corpus-Driven Input-Based and Output-Based Instruction Zia Tajeddin 1* , Ensieh Khodarahmi 2 1* Professor of Applied Linguistics, Allameh Tabataba‟i University, Iran; zia_tajeddin@yahoo.com 2 Ph.D. Candidate of TEFL, Allameh Tabataba‟i University, Iran; ensieh.khodarahmi@gmail.com Abstract Mainstream L2 pragmatic research has shown that pragmatic fossilization is quite common among L2 learners at almost all levels of proficiency. This study examined the defossilizing effect of corpus-driven activities on 10 situationally-based pragmatic routines under two instructional conditions, i.e. input-based and output- based treatments. Participants were 33 advanced EFL learners in two classes in a private English language center. They received instruction in four sessions across two weeks. Before and after the treatment, a WDCT was administered for pretest and posttest purposes. The results of paired-samples and Independent Samples t- tests showed that input-enhancement and output-based instructions were effective in defossilization pragmatic routines which had a strong fossilization tendency among learners. Both treatment tasks led to significant increases in learners‟ comprehension and production of the routines. The output-based group; however, significantly outperformed the input-based group in the production of the routines. The findings indicate that pragmatic instruction can debilitate the fossilization tendencies of pragmatic routines and that different instructional tasks have differential effects on the production and comprehension of pragmatic routines. The pedagogical implication of this study is that a combination of instructionally supported corpus- based tasks would be effective for enhancing EFL learners‟ ability to comprehend and use routines appropriately in context. Keywords: Defossilization, Input-based instruction, Output-based instruction, Pragmatic fossilization, Pragmatic routines Received 24 March 2019 Accepted 28 May 2019 Available online 25 June 2019 DOI: 10.30479/jmrels.2019.10523.1317 © Imam Khomeini International University. All rights reserved.