Corrective feedback via e-mail on the correct use of past tense among Iranian EFL learners

This study explores the differential effect of two types of corrective feedback strategies – explicit and implicit – on the acquisition and retention of correct past form of irregular verbs by Iranian English as Foreign Language (EFL) learners. Sixty out of 80 pre-intermediate EFL learners were selected as the participants, based on their performance on Key English Test (KET); their scores were between one standard deviation (SD) above and below the mean (M). Thereafter, they were randomly assigned into two experimental groups: the explicit group (N = 30) who received explicit corrective feedback and the implicit group (N = 30), who received implicit feedback. Results indicate that the explicit group outperformed the implicit group on the immediate and delayed post-tests. The findings of this study have theoretical and pedagogical implications for teachers. Feedback strategy provides teachers with information on effective teaching and student comprehension, and encourages them to use technology in a way that reduces anxiety and facilitates social learning.

teaching and learning, new activities, new products, and new types of learning possible (Kozma & Schank, 1998, cited in Murchú, 2005.
Warschauer (1995( , cited in Hosseini, 2013) emphasises the role of e-mail in CMC, and says that e-mail is the most important application regarding the internet. According to Barson, Frommer andSchwartz (1993, cited in Hosseini, 2013), using computer technologies can help learners increase their opportunities to use the target language. Electronic mail (e-mail) provides immediate feedback and allows students to discuss and communicate directly, cheaply, quickly, and reliably. Previous research suggests that email can facilitate communication (Cooper & Selfe, 1990, cited in Alzu'bi & Sabha, 2013, reduce anxiety (Kern, 1995, as cited in Alzu'bi & Sabha, 2013, facilitate social learning (Belz, 2002, cited in Alzu'bi & Sabha, 2013, and improve writing skills (Warschauer, 1996, cited in Alzu'bi & Sabha, 2013. In a study by Mushangwe (2014), 20 participants from different African countries studying Chinese for three months at Hebei University, were investigated using the voice recognition application on smartphones. The researcher used tablets for pronunciation practice purposes, to boost students' confidence in spoken Chinese. Here, the technology is used as the decoding person representing how a native Chinese will decode the learner's speech. The results indicated that during the exercise, participants become better aware of their errors and corrected their pronunciation. In addition, technology helped them to find the pronunciation stability of the learners. Based on this study, it was concluded that game-like traits of voice recognition application on smartphones help language learners to exercise spoken Chinese. It can be stated that this approach elevates selfevaluation and interest in learning any language.
This study investigates the effect of corrective feedback through e-mail on the correct use of the past forms of irregular verbs by Iranian preintermediate EFL learners in written communication format. In Iran, no attempt has ever been made to assess the effectiveness of corrective feedback via email in the correct use of English past tense. Therefore, the findings of this study might help to enhance the practices of EFL for teachers and learners. Previous studies have revealed that high school students have a great deal of problems with target language syntax and proper use of structures. Therefore, this study attempts to accentuate syntactic and structural problems and offer strategies to enhance learners' ability to successfully deal with problems of this sort.
To do so, this study addresses two major questions: 1. Is implicit feedback via email more effective than explicit feedback via email in acquisition of the correct past tense of irregular verbs by Iranian EFL learners? 2. Is implicit feedback via email more effective than explicit feedback via email in retention of the correct past tense of irregular verbs by Iranian EFL learners?

Methodology Participants
The population from which participants were chosen included 80 female Iranian pre-intermediate EFL learners. Their native language was Persian. From among them, 60 learners were selected as the participants of the study based on their performance on KET (2009), developed by Cambridge; their scores fell between one SD above and below the M. Thereafter, they were randomly assigned into two groups: experimental group 1 (N = 30) that received explicit corrective feedback and experimental group 2 (N = 30) that got implicit feedback after sending their mail to the researcher. The limited number of learners at the mentioned high school did not allow the researcher to have a control group similar to experimental groups. These participants took part in this study voluntarily, according to their access to the internet out of the class sessions and were presented with their regular course books developed by the Ministry of Education in Iran.
In addition to these students and the researcher, an experienced teacher took part in this study. The experienced teacher, familiar with different teaching strategies, had the responsibility of teaching English past tense during treatment.

Instruments
To answer the research questions presented by the researcher, the following instruments were used: placement test (KET), English Book 1, the internet and email, and two post-tests.

Key English test (The KET)
The KET used in this study was the test developed by Cambridge in 2009. KET is an elementary level qualification. It covers everyday practical English, and helps learners to understand simple questions and instructions (Green & Jay, 2005). The test has 56 reading and writing items, for which one hour and 10 minutes is allotted for answering. Each item has one score, and the last one has five scores, so these skills make up 50 percent of the total score. Listening items need 25 minutes, and the allotted time for speaking is 8-10 minutes. The total score for the test is 100; listening and speaking carry 25 percent of the final mark. The candidates' scores allow them to see how they performed. The reliability of this test was assured by administering it to a group similar to the participants. The Kuder and Richardson Formula 21 (KR-21) reliability index for the KET was .85. This test was administered as a language proficiency test prior to the treatment to make sure that the participants were of approximately equal level of language proficiency and of grammar knowledge.

Course book
The "English Book 1" developed by the Ministry of Education in Iran was used during the experiment. This textbook is taught three hours per week in Iranian high schools. It includes nine lessons. Each

Immediate and one-week delayed post-test
Two post-tests -immediate and delayed -were used to determine the effect of explicit and implicit feedback on the acquisition and retention of correct past tense of irregular verbs, respectively. The immediate post-test, administered immediately after the treatment, was an International English Language Testing System (IELTS) test, which included 25 grammatical items about the past tense. The first part of these items included 17 multiple-choice questions, where the students had to select the correct form of verbs. The second part consisted of two simple paragraphs with eight blanks; the students had to fill in the blanks and write the correct form of the verbs by means of the words enclosed within the parentheses, and in the third part, they had to write a paragraph about an event which was related to their childhood. It is worth mentioning that all the topics and tests were within the participants' vocabulary and grammar knowledge.
The delayed post-test was given to students one week after the treatment. This test included a writing activity requiring participants to write a paragraph about their previous trip. The length of the paragraph had to be between 20-30 sentences. They had to use the correct form of past tense verbs.

Design and Procedure
The present study was conducted in a quasiexperimental design, as there was no true random-isation. The students were placed in classes on the basis of certain criteria, such as their scores on the KET and their access to the internet. They were divided into two groups, Experimental Group 1 that received explicit feedback, and Experimental Group 2 that got implicit feedback after sending their mail, writings on the topics provided, to the researcher. The limited number of learners in the mentioned high school did not allow the researcher to have a control group similar to experimental groups.
The teacher taught English past tense as well as irregular verbs and provided the participants with eight writing topics during the experiment, once a week, for eight weeks. Students were required to send their writing to the researcher through e-mail. Having received the feedback, the participants of the experimental groups were compelled to send their modified output as an independent e-mail prior to receiving the next new topic, in order to make sure of the students' noticing the researcherprovided feedback.
Experimental Group 1 received explicit feedback, that is, having identified that an error had been made, the researcher indicated it and provided the correction; the correct form was required to be used by the participants in their modified output.
Example (1) Experimental Group 2 received implicit repetition feedback, that is, having highlighted the error by means of emphatic stress or underlined bolded uppercase words, the researcher repeated the learner's utterance, of which reformulation by the participants was required in the modified output. It was emphasised that the underlined bolded uppercase words had nothing to do with spelling mistakes.
Example (2) At the end of the treatment, the researcher gave the two mentioned post-tests to the participants in order to determine the extent to which the treatment was successful in enhancing their ability to correctly apply simple past tense. Learners' improvement in using correct past form of irregular verbs was assessed through items included in the post-tests: writing a composition, completion test, filling in the blank, and changing the sentences into simple past tense.
The participants had to use the correct form of past tense verbs. Whenever they wrote the verbs correctly, they got the mark.
The immediate post-test was an IELTS test, which included 25 grammatical items about past tense. The total score for grammatical items was 25, with each item worth one mark. The first part of these items included 17 multiple-choice questions that the students had to select the correct form of verbs. The second part included two simple paragraphs with eight blanks that students filled in and wrote the correct form of the verbs by means of the words enclosed within the parentheses. In the third part, they had to write a paragraph about an event related to their childhood. If they wrote a complete composition with 20-30 sentences and used the correct form of past tense verbs, they would get 10 marks. This test was administered to determine the effect of the mentioned feedbacks on the acquisition of correct past tense of irregular verbs by the participants.
The delayed post-test included a writing activity for each student, where they were required to write a paragraph about their previous trip. The length of the paragraph had to be between 20-30 sentences, and the participants did their work in the classroom. The total score for writing the assignment was 25. If they wrote a composition of 20-30 sentences and used the correct form of the past tense verbs, they would get 10 marks. The researcher administered this test to determine the effect of implicit and explicit feedback on the retention of correct past tense of irregular verbs by the participants.
The scores for two post-tests entered into an Excel worksheet as either correct (1); or incorrect (0); based on whether the students were able to produce the target form in written output in English. Whenever a student answered correctly, she got one mark for the correct output.

Data Analysis
The gathered data was analysed by using the Statistical Package for the Social Sciences (SPSS) program presenting descriptive statistics of frequency to find the most and the least scores of Iranian EFL learners for using the correct form of simple past tense. In addition, to see whether there was any significant difference between two groups in acquisition and retention of correct past form of irregular verbs, regarding explicit or implicit feedback received by them, the parametric independent t-tests were used.

Testing Assumptions
This study investigates the effect of two types of feedback -explicit and implicit -on the acquisition and retention of correct past tense of irregular verbs by Iranian EFL learners. An independent t-test was used to compare the groups' performance on the immediate and delayed post-tests.

KET, General Language Proficiency Test
In order to have participants of approximately equal level of language proficiency, the researcher administered the KET general language proficiency test to 80 EFL learners. Sixty students who scored between 1 standard deviation below and above the mean were selected to participate in the study. The descriptive statistics for the KET are displayed in Table 1.

Testing Research Hypothesis 1
In response to the first research question concerning the differential impact of explicit and implicit corrective feedback on acquisition of correct past tense of irregular verbs, the groups' means were compared. As it is evident from Table 2

Testing Research Hypothesis 2
In response to the second research question concerning the differential impact of explicit and implicit corrective feedback on retention of correct past tense of irregular verbs, the groups' means were compared. As Table 3 displays, the Explicit group (M = 26.07, SD = 2.13) showed a significantly higher rate of retention than the Implicit group (M = 22.30, SD = 2.53).

Discussion
The present study was an attempt toward investigating the effect of explicit and implicit feedback via email on acquisition and retention of the correct past tense form of irregular English verbs by Iranian EFL learners. Therefore, the following two hypotheses were formulated: H1: Implicit feedback via e-mail is more effective than explicit feedback via email in acquisition of the correct past tense of irregular verbs by Iranian EFL learners. H2: Implicit feedback via e-mail is more effective than explicit feedback via email in retention of the correct past tense of irregular verbs by Iranian EFL learners.
As far as the first hypothesis is concerned, the results of an independent t-test revealed a significant difference between the two groups' performance on the immediate post-test, administered to determine the effect of implicit and explicit feed-back via e-mail on acquisition of the correct past tense of irregular verbs. The explicit group (M = 30.07, SD = 4.63) outperformed the implicit group (M = 21.87, SD = 3.74) on the immediate post-test. In other words, it appears conclusive that the Iranian EFL learners have acquired the past tense better, when using the explicit feedback strategy of teaching grammar.  Note: * = p > .05. Since (p) was 0.05, hypothesis two was rejected.
The second hypothesis was tested by applying the independent t-test. The results indicated a significant difference between the two groups' performance on the delayed post-test, administered to determine the effect of implicit and explicit feedback via email on retention of the correct past tense of irregular verbs. That is, the Iranian EFL learners have retained the past tense better using the explicit feedback strategy of teaching grammar. This can be due to a variety of factors; when Iranian EFL learners make a mistake, generally, they tend to rely on their teachers to provide them with correct structures. So, they react when teachers explicitly identify the error, correct it, and require them to modify their language. As a result, they tend to use erroneous structures less frequently, for which teachers provide some clues.
In this study, Experimental Group 2 (implicit group) simply failed to notice the researcherprovided feedback, because the participants did not receive any information on the formal aspects. Second, the bolded uppercase words may have misguided them into wrongly correcting and changing the word itself, or adding unnecessary words without realising incorrect parts.
Psychological factors may affect the participants' performance on tests. It can be claimed that reminding learners of their mistakes in the presence of their classmates might have acted as psychological barrier to their uptaking of the teacher provided feedback and resulted in inefficacy of the treatment. To minimise the negative effect of such factors, the researcher provided the participants with feedback through e-mail; since previous research suggests that email can facilitate communication (Cooper & Selfe, 1990, as cited in Alzu'bi & Sabha, 2013, reduce anxiety (Kern, 1995, cited in Alzu'bi & Sabha, 2013, facilitate social learning (Belz, 2002, cited in Alzu'bi & Sabha, 2013, and improve writing skills (Warschauer, 1996, cited in Alzu'bi & Sabha, 2013. Participants themselves asked the researcher not to be reminded of their mistakes in the presence of their classmates.
According to the findings of this study, feedback strategy provides teachers with data on effective teaching and student comprehension, and CMC encourages them to use technology in pedagogical environments. It may be more effective to think about CMC and using it for Iranian EFL learners as a suitable way to increase negotiation of meaning, because students are forced to use English through e-mail, although teachers can create significant learning through giving the appropriate feedback. As Brown (2000, cited in Hosseini, 2013 mentions, negative feedback can cause frustration for students, so they perceive that their writings are disastrous, but computers in the writing class have been shown to have a generally positive impact on students' performance in language acquisition. Teaching English as a foreign language (TEFL) teachers who use technology in their classes should know that the successful use of email for educational purposes will be largely determined by how well it meets the identified needs of their learners.
Some other studies highlight the positive effect of technology on improving different language skills as well as components. Findings of the study conducted by Motallebzadeh and Amirabadi (2011) indicated that e-collaboration/e-partnering could improve learners writing skills if integrated into the EFL curriculum designed for pre-intermediate level.
In their study on Asynchronous Computer Mediated Communication (ACMC), St. John and Cash (1995) found that an adult language learner dramatically improved his German via e-mail exchanges with a native speaker. They concluded that ACMC via email exchanges could improve learners' grammar and linguistic awareness through corrective feedback (cited in Hosseini, 2013).
This study provides valuable findings in the education field, but some limitations are attributed to this study. First, the level of proficiency of learners was low, and it was possible that more proficient learners would have performed differently. Second, the study did not have any control group, because the researcher could not access a group with similar characteristics and a large number of participants. Third, it should be accepted that most previous research on corrective feedback and positive contributions to grammar accuracy and different English tenses have been conducted in written, oral, and chat forms. Therefore, generalisations to asynchronous computer-mediation via email, especially in EFL environments, should be done with great caution.

Conclusion
On the basis of the results of the present study, it became evident that explicit corrective feedback had a significant effect on increasing the correct use of English past tense. However, implicit corrective feedback did not have any significant effect on Iranian EFL learners regarding the second experimental group's performance. The findings of the present study also had further implications as to the efficacy of computer-mediated feedback as a medium on different aspects of language grammar.
One of the advantages of CMC in many general educational situations is the immediacy of feedback (Atkinson & Davis, 2000, cited in Najafi, 2007. Choen (2003( , cited in Dadabeigloo, 2011 believes that classroom conversation includes teacher interaction, student response, and teacher follow up. In Iranian L2 classrooms, real conversation rarely happens. However, Iranian students usually use their first language to solve their communication problems (conversation breakdown) in real exchanges. Consequently, this often does not lead to meaningful negotiation in English. Accordingly, it may be more effective to think about CMC and using it for Iranian EFL learners as a suitable way to increase negotiation of meaning; email can materialise this to some extent.
Despite the limitations mentioned, it is believed that the findings of this study are encouraging as technology has been finding its way into pedagogical environments. Feedback is commonly used in the classroom, but it is essential to investigate the efficacy of technology and its further implications in EFL classes, because the increasing use of technology for feedback purposes has been less explored. Additionally, and with respect to the results of this study, it should be mentioned that the study indicates that technology has an important role not only for Iranian learners, but also for all around the world including South Africans. Furthermore, for Iranian and other researchers, there is still plenty of room for further research in this field.