The aim of this study was to explore the effect of computer-mediated communication (CMC), as compared with traditional face-to-face instruction, on the acquisition of the request speech act. It also examined the differential impacts of synchronous and asynchronous CMC modes on pragmalinguistic and sociopragmatic competences. The participants were 106 Iranian EFL learners who received the treatment via synchronous (Syn), asynchronous (Asyn), and face-to-face (F-F) instruction types for eight sessions during an intensive extracurricular program. During each of the treatment sessions, the participants received the metapragmatic instruction; watched computerized video clips on requests; and then were paired with a partner to discuss some prescribed questions and to create their own dialogues based on the given situations. During this phase, they were engaged in synchronous text-based chat, asynchronous text-based chat, or face-to-face discussion, based on their group assignment. Prior to and after the treatment, the written discourse completion test (WDCT) pretest and post-test were administered. The data analysis by an ANCOVA and a series of t-tests showed the superiority of CMC-oriented instruction over F-F instruction. While no significant difference was found between Syn and Asyn groups in their post-test performance, they performed differentially on some measures of pragmalinguistic and sociopragmatic competences. The findings havepedagogical implications for EFL teachers, practitioners, and courseware designers to use CMC affordances for delivering pragmatics instruction.
