The Effect of Comprehensible Input and Comprehensible Output on the Accuracy and Complexity of Iranian EFL Learners’ Oral Speech

Document Type: Research Paper


Islamic Azad University, Najafabad Branch


This study aimed at investigating the relative impact of comprehensible input and comprehensible output on the development of grammatical accuracy and syntactic complexity of Iranian EFL learners’ oral production. Participants were 60 female EFL learners selected from a whole population pool of 80 based on the standard test of IELTS. To investigate the research questions, the participants were randomly divided into three groups: Input group, output group, and control group. The study involved two phases: the pre-task phase, and the main-task phase. During the pre-task phase, the input group received comprehensible input. In the same phase, the output group was pushed to be engaged in comprehensible output production. The control group neither received input, nor was engaged in output production. In the main-task phase, all subjects performed monologues that were separately recorded, and later transcribed and coded in terms of accuracy and complexity through Bygate's (2001) standard coding system and finally scored. The statistical analysis of the results revealed that while the output group outperformed the input group in grammatical accuracy, the input group proved to be more rigorous and influential in developing speech complexity. The study supports Swain’s (1985) claim that there are roles for comprehensible output that are different from and independent of comprehensible input, and Skehan & Foster's (2001) theory regarding human beings’ limited attentional capacities that can be devoted to one aspect of oral speech at the expense of the other. Generally, it is implied that the most effective way for improving oral speech, based on the literature and the results obtained from this study, is an eclectic approach which conflates both comprehensible input and comprehensible output.


Bygate, M. (1999). Task as context for the framing, reframing, and unframing of language.  System, 27, 33-48.

Bygate, M. (2001). Effects of task repetition on the structure and control of oral language. In M. Bygate, P. Skehan, & M. Swain (Eds.), Researching pedagogic tasks: Second language learning and testing (pp. 37-53). London: Longman.

Dekeyser, R, & Sokalski, K. (1996). The differential role of comprehension and production practice. Language Learning, 46(4), 613-642.

D’Ely, R. C. F. (2006). A focus on learners’ meta-cognitive processes: The impact of strategic planning, repetition, strategic planning plus repetition, and strategic planning for repetition on L2 oral performance. Unpublished Doctoral Dissertation, University of Santa Catarina.

Ellis, R. (2008). Principles of instructed second language acquisition. CALL(Center for Applied Linguistics). Retrieved September 25, 2009 from                                                                                http://

Faerch, C., & Kasper, G. (1986). The role of comprehension in second language learning.            .         Applied Linguistics, 7(3), 257-274.

Finardi, R. K. (2008). Effects of task repetition on L2 oral performance. Scielo, 47(1). Retrieved November 25, 2009 from                                                                                                                          http://

Foster, P., & Skehan, P. (1996). The influence of planning and task type on second language performance. Studies in Second Language Acquisition, 18, 229-323.

Fulcher, G. (2003). Testing second language speaking. TESL, 8(1). Retrieved June, 2004 from                                                                                                                                               http:// 29/r5.html.

Harati, N. (2000). The impact of recast versus negotiation of form on the grammatical accuracy of Iranian EFL students’ speech. A Thesis Submitted in Partial Fulfillment of the Requirements for the Degree of Master of Arts in Teaching English as a Foreign Language. In the Foreign Languages Department of Iran, University of Science and Technology.

Iwashita, N. & McNamara, T. & Elder, C. (2002). Can we predict task difficulty in an oral proficiency test? Exploring the potential of an information processing approach to task design. Language learning, 51(3), 401-436.

Izumi, S. (2002). Output, input enhancement, and the noticing hypothesis. Studies in Second Language Acquisition, 24, 541-577.

Krashen, S. D. (1981). Principles and practice in second language acquisition: English Language Teaching Series. London: Prentice-Hall International (UK) Ltd.

Krashen, S. D. (1982). Principles and practice in second language acquisition. Oxford:     Pergamon.

Krashen, S.D. (1985). The input hypothesis: Issues and implications. London: Longman. 

Krashen, S. (1994). The input hypothesis and its rivals. In N. Ellis (Ed.), Implicit and explicit learning of languages (pp. 45-77). London: Academic Press.

Mackey, A. (1999). Input, interaction, and second language development: An empirical study of question formation in ESL. Studies in Second Language Acquisition, 21, 557-587.

Mangubhai, F. (2001). Book floods and comprehensible input floods: Providing ideal conditions for second language acquisition. International Journal of Educational Research, 35,147-156.

Nagata, N. (1998). Input vs. output practice in educational software for second language acquisition. Language Learning & Technology, 1(2), 23-40.

Nobuyoshi, J., & Ellis, R. (1993). Focused communication tasks and second language acquisition. ELT Journal, 47, 203-210.

Ryan, J. (n.d.). A review of the role of the output in second language acquisition with anecdotal examples from a Japanese learner’s experience. Language Learning, 38(17), 42-54.

Schutz, R. (2007). Stephen Krashen’s theory of second language acquisition.Retrieved  November, 2007 from                                                                           

Shehadeh, A. (2002). Comprehensible output, from occurrence to acquisition: an agenda for acquisitional research. Language Learning, 52(3), 597-647.

Skehan, P . (1998). A cognitive approach to language learning. Oxford: Oxford University Press.

Skehan, P. & Foster, P. (1997). Task type and task processing conditions. Language Teaching Research, 3(1), 185-211.

Skehan, P. & Foster, P. (2001). Cognition and Tasks. In Robinson, P. (Ed.), Cognition and   second language instruction (pp. 183-205). Cambridge: Cambridge University Press.

Soleimani, H. & Ketabi, S. & Talebinejad, M. (2008). The noticing function of output in  acquisition of rhetorical structure of contrast paragraphs of Iranian EFL university students. Linguistic Online. Retrieved April, 2008 from                                                                               http:// www.

Swain, M. (1985). Communicative competence: some roles of comprehensible input and comprehensible output in its development. In Gass,S; & Madden, C. (EDs), Input in second language acquisition (pp.235-256). Newyork. Newbury House.

Swain, M. (1995). Three functions of output in second language learning. In G. Cook & B. Seildlhofer (Eds.), Principles and practice in applied linguistics: Studies in honor of H.G. Widdowson (pp. 125-144). Oxford: Oxford University Press.

Swain, M. (2008). The output hypothesis: its history and its future. A keynote speech in The 5th Annual International Conference on ELT in Beijing. Retrieved March 1, 2008 from

Swain, M. & S. Lapkin (1995). Problems in output and the cognitive processes they generate: A step towards second language learning. Applied Linguistics, 16, 371-391.

Tarone, E., & Liu, G.Q. (1995). Situational context, variation, and second language acquisition theory. In G. Cook & B. Seidelhofer (Eds.), Principle and practice in applied linguistics: Studies in honor of H. G. Widdowson (pp.107-124). Oxford: Oxford University Press.