The impact of opinion-gap, reasoning-gap, and information-gap tasks on EFL learners’ speaking fluency

Abstract This study was an attempt to compare the effects of using opinion-gap, reasoning-gap, and information-gap tasks on Iranian EFL learners’ speaking fluency. To fulfill this objective, 140 intermediate EFL learners were selected and subsequently divided into three experimental groups including opinion-gap group, reasoning-gap group, and information-gap group, plus one control group. Afterward, the participants of all the groups were given a speaking pre-test, followed by the intervention, where the experimental groups received their specific treatments and the control group was exposed to the placebo. After the intervention ended, a speaking post-test was given to all the groups in order to measure the effects of the treatments on their speaking fluency. The results of one-way ANOVA indicated that the three experimental groups outperformed the control group on the post-test. In addition, the results uncovered that information-gap tasks were more effective than opinion-gap tasks and reasoning-gap tasks. In light of these findings, the researchers suggested some recommendations that are hoped to help syllabus designers, supervisors and English language teachers in developing teaching speaking skills.

Abstract: This study was an attempt to compare the effects of using opinion-gap, reasoning-gap, and information-gap tasks on Iranian EFL learners' speaking fluency. To fulfill this objective, 140 intermediate EFL learners were selected and subsequently divided into three experimental groups including opinion-gap group, reasoning-gap group, and information-gap group, plus one control group. Afterward, the participants of all the groups were given a speaking pre-test, followed by the intervention, where the experimental groups received their specific treatments and the control group was exposed to the placebo. After the intervention ended, a speaking post-test was given to all the groups in order to measure the effects of the treatments on their speaking fluency. The results of one-way ANOVA indicated that the three experimental groups outperformed the control group on the posttest. In addition, the results uncovered that information-gap tasks were more effective than opinion-gap tasks and reasoning-gap tasks. In light of these findings, the researchers suggested some recommendations that are hoped to help syllabus designers, supervisors and English language teachers in developing teaching speaking skills.

PUBLIC INTEREST STATEMENT
Task-based learning is a different way to teach languages. It can help students by placing them in real-life situations, where oral communication is essential for doing a specific task. Task-based learning has the advantage of getting students to use their skills at their current level, developing language through its use. It has the advantage of placing the focus of students toward achieving a goal where language becomes a tool, making the use of language a necessity. With regard to the vital role of tasks in language teaching and learning, this study considered three kinds of tasks, namely, opinion-gap, reasoning-gap, and information-gap tasks and tried to check their effects on improving Iranian EFL learners' speaking fluency. After implementing the treatment sessions, it was revealed that the three mentioned tasks enhanced the Iranian EFL learners' speaking fluency.

Introduction
The most imperative function of language for human beings is to communicate meaningfully with each other; humans first need to understand the language used among them to communicate their meaning and intention (Hasan, 2014). This means speech is the primary skill in the language arts; speech is the fundamental first tool of expression for conveying information, feelings, emotions, ideas, and beliefs. This further implies that speaking, long before reading or writing, is the first stage of language learning, even when learning a new second or foreign language. Abdallah and Mansour (2015) confirm that language learning requires giving attention to speaking skills, acquiring realistic usages and contextual-pragmatic practices. Other skills such as reading and writing are equally important in advanced language usage, as they enhance eloquence and comprehension; however, speaking takes precedence.
Speaking skill includes fluency and accuracy, but this study deals only with fluency. Since Iranian EFL learners are not fluent enough in English to initiate and maintain their conversations successfully, this study aims to improve their English fluency. Hartmann and Stork (1976) assert that the term "fluent" means a speaker is able to use the correct structures of a language at normal speed, which means speaking naturally with concentration on the content delivery, rather than focusing on the form or structure of a language. Fillmore (1979) defines four abilities of speaking fluently: a) the ability to talk at length with few pauses; b) be able to state the sentences coherently and semantically; c) have appropriate expressions in a wide range of contexts; d) be creative and imaginative in language use. Generally speaking, speaking is a crucial part of second language learning and teaching. Despite its importance, for many years, teaching speaking has been undervalued and English language teachers have continued to teach speaking just as a repetition of drills or memorization of dialogues. However, today's world requires that the goal of teaching speaking should improve the students' communicative skills, because only in that way, students can express themselves and learn how to follow the social and cultural rules appropriate in each communicative circumstance.
With regard to the statement above, one of the basic problems in foreign language teaching is the English speaking ability of Iranian intermediate EFL learners is weak. The failure of the teaching speaking can be caused by internal and external factors. These factors are: the bad quality of teacher's skills in the teaching of English and their inability in teaching speaking, the domination of teaching structure and reading, the limited time for teaching speaking, the large number of students in a class, and sometimes the students do not have strong motivation to learn English language, especially speaking, so the students are not interested in this subject and in the environmental conditions. Furthermore, to overcome these problems and prepare students to be able to use the English language in communication is not easy.
In this final project, information-gap, opinion-gap, and reasoning-gap tasks are proposed as the three of the techniques that can be used by the English teacher as ways in teaching speaking for the Iranian students. They can be used to break the boring and monotonous situation in the teaching English and particularly in learning speaking. As a matter of fact, there are various techniques of teaching speaking. However, information-gap, opinion-gap, and reasoning-gap tasks are useful to support the student's success in learning English. Hopefully, the students are able to use the language for communication.
An information-gap task is a technique in which learners are missing the needed information to complete a task or solve a problem, and they have to communicate with their classmates to fill in the gaps (Larsen-Freeman, 2003). For example, learners share their information to complete a class timetable, or learners need to share information about their families and then draw each other's family trees. Opinion-gap task requires the learners to give their own personal preference, feeling, or attitude to complete a task (Fallahi, Aziz Malayeri, & Bayat, 2015). For example, a social problem such as "divorce" can be given to the learners and be asked to give their ideas on how to tackle it. Reasoning-gap task refers to the new information that are derived by the students through inference, deduction, practical reasoning, or perception of relationships or patterns (Prabhu, 1987). Prabhu (1987) believed that tasks should involve learners in "reasoning"-making connections between the information. Through requiring the leaners to provide reasons while learning new materials we as teachers can help them to learn English language better.
In summary, nobody can deny the fact that speaking is one of the important and essential skills that needs a lot of practice to communicate. People who have the ability in speaking will receive the information better. As a matter of fact, language is not only taught and learned, but it is used as a habit. Therefore, students of English must be able to speak English well because people identify the English mastery with their English speaking. From the researcher`s short experience as a teacher, she noticed that many teachers teach student passively. They let the students only memorize the vocabulary, ask the students to open the exercise book, read the task, and then do the exercise. Then the teacher asks the students to write the words without asking the student to use it in real communication. Hence, some students do not know the function of this language exercise. As a result, the students are not interested in the English learning process. They become passive in English learning and they are not able to speak. Therefore, this English teaching/learning process is not effective. In the current study, the researcher tried to propose a solution for the teachers to implement one of the teaching techniques and help students to develop their oral communication skills in English. Information gap, opinion gap, and reasoning gap are interesting technique, and they can improve students' ability. Accordingly, the researchers decided to investigate the effectiveness of using these three tasks on developing speaking skills for the intermediate learners in a private language institute.  Aliakbari and Jamalvandi (2011), speaking is an interactive process of constructing meaning that involves producing and receiving and processing information. Then, it is often spontaneous, open-ended, and evolving, but it is not unpredictable. Moreover, most of the people prefer to communicate orally with each other because they can take and give the direct responses of their interlocutor.

Review
Nevertheless, people who want to be able to communicate through speaking for all languages, they should learn it seriously. Because of speaking in foreign language is very difficult, people should not only know a certain amount of knowledge of grammar and vocabulary in English, but also practice communicating through socialization in their social environment continuously. As stated by Namaziandost, Abdy Saray, and Rahimi Esfahani (2018), for most people, the ability to speak a language is synonymous with knowing that language since speech is the most basic means of human communication.
In teaching learning English as a foreign language, speaking can be defined as the productive and oral skill which consists of producing systematic verbal utterances to convey meaning (Bailey, 2005). It means that in active and productive skill, students should use all and any language at their mind to achieve a certain communicative purpose. Then, according to Harmer (2001:269), the ability to speak fluently presupposes not only knowledge of language features, but also the ability to process information and language on the spot. Fluency has been defined by Ellis (2004) as "the extent to which the language produced in performing a task manifests pausing, hesitation, and reformulation" (p.342). Mizera (2008) states that "fluency is defined as the ability to spontaneously speak a language quickly and comprehensively without an undue number of formal errors that distract listeners from the speaker's message" (p.3). According to Hedge (2000), fluency is the ability to link units of speech together with facility and without strain or inappropriate slowness of hesitation.
Actually, the goal of teaching speaking skills is communicative efficiency. Students should be able to make themselves understood, using their current proficiency to the fullest. Students need to be able to speak English with confidence in order to carry out many of their basic communication to another person. In other words, speaking is the skill that the students will be judged upon most in real-life situations. It is an important part of everyday interaction and most often the first impression of a person is based on his/her ability to speak fluently and comprehensively. Therefore, the English language teachers have a responsibility to prepare the students as much as possible to be able to speak in English in the real world outside the classroom and the testing room.
According to Harmer (2007), there are three main reasons for getting students to speak in the classroom. Firstly, speaking activities provide rehearsal opportunities-chance to practice real-life speaking in the safety of the classroom. Secondly, speaking tasks in which students try to use any or all of the languages they know provide feedback for both teacher and students. And finally, the more students have opportunities to activate the various elements of languages they have stored in their brains, the more automatic their use of these elements become. As a result, students gradually become autonomous language users. These mean that the students will be able to use words and phrases fluently without very much conscious thought. Therefore, it is essential for English language teachers to pay great attention to teaching speaking. Rather than leading students to pure memorization, providing a rich environment where meaningful communication takes place is desired. They should create suitable, enjoyable and meaningful activity or task which can engage the students to practice speaking seriously. As stated by Harmer (2007), Good speaking activities can and should be extremely engaging for the students. If they are all participating fully-and if the teacher has set up the activity properly and can then give sympathetic and useful feedback-they will get tremendous satisfaction from it. With this aim, various speaking activities can contribute a great deal to students in developing basic interactive skills necessary for life. These activities make students more active in the learning process and at the same time make their learning more meaningful and fun for them (Namaziandost, Rahimi Esfahani, Nasri, & Mirshekaran, 2018). Ahmed and Bidin (2016) trace TBLT back to the principles and teaching of experiential learning, as first developed by John Dewey in the 1890s. Dewey wrote extensively about how real-life experiences could be practiced in a classroom designed to enhance learning. According to Ahmed and Bidin (2016), Dewey was concerned with how theoretical learning could be transformed to allow students to participate in the pragmatic activities they learned in class. Dewey felt that allowing learners to interact with the practical activities would give them new insights and ultimately make them more productive when they entered into the workforce or higher education markets. These concepts were later introduced into communication strategies in the twentieth century which sought to establish how people from different backgrounds could embrace experiential learning to understand each other. Communication strategies were used for language learners visiting the community of the target language, to be assimilated and eventually master the language, as opposed to learning it in book didactically. Ahmed and Bidin (2016) claim that task-based learning was popularized in the 1980s by Prabhu when he used it in a Communication Language Teaching project in India. Prabhu (1987) was perturbed by the lack of impact in the traditional approaches used in teaching foreign language, and decided to embrace real-life activities and experiences in language learning. Ahmed and Bidin (2016) assert that Prabhu found that traditional didactic methods only provided abstract information, on the mistaken assumption that learners would easily memorize and practice the whole grammar of the target language. Unfortunately, these methods were not efficient as it was evident that learners could not communicate effectively in real-life situation in the target language. Prabhu noticed these gaps and utilized a task-based approach to tap the student's natural mechanism in learning the target language which proved to be effective especially in handling real-life situation (Ahmed & Bidin, 2016).

Task-based language learning (TBLT)
In this connection, Ganta (2015) argues that the fundamental reason for the task-based revolution was the fact that it enabled students to engage in intense verbal interaction, as opposed to a teacher-student interaction. Seyyedi and Ismail (2012) imply that it provided learners an opportunity to participate in communication using the target language to accelerate their language acquisition. Generally speaking, task-based practice enhances comprehension and development of the cognitive aspects of the communicative skills. Prabhu (1987) says that this method was more participatory, and avoided the rote learning processes of inputting knowledge without putting it into practice. Additionally, in the Communication Language Teaching project in India, Prabhu (1987) noted that TBLT provided leeway for working in groups which were an alternative to individual work. In group work, learners get to work in co-operation and coordination lifting their morale and their urge to know more about the subject.
Further, Ganta (2015) observes that the traditional language teaching methods overlooked the authentic aspects of the traditional methods which are fundamental in learning the target language. Learners could be acquainted with the grammatical syntax that was taught by the teacher, but they did not get the core language tools and idioms that are primarily associated with the target language. Prabhu (1987) also noted that assigning the students task-based assignments gave them an opportunity to assimilate skills and idioms that would otherwise be challenging to teach in a classroom. Ultimately, the TBLT approach was quite successful in the Communication Language Teaching project in India, prompting Prabhu to promote TBLT as a new and more effective method of teaching second and target languages (Ganta, 2015). Since this point, the TBLT method has also been widely used to help learners in the acquisition of the second language in a conventional classroom setup.
Ellis (2009) defined a task as any activity that requires learners to embrace the target language, focusing on the meaning in order to attain a certain goal or perform a certain action. Learners engage in a set of lesson plans that are interactive, to aid them in comprehending and manipulating the target language. Ellis (2009) also notes that tasks embrace a cognitive process that involves selecting, reasoning, classifying, sequencing information, and transforming that information from one form to the other.
According to Ellis (2009), there are four characteristics that extensively define a task. First, a task is pragmatic; that is, it has to focus primarily on the meaning. Second, the task has to have a clearly defined non-linguistic outcome. Thirdly, the participants or learners are at liberty to choose the linguistic resources that are needed in completing the task. Lastly, the task should have some kind of procedures or steps, to enable learners to fill in "gaps" to comprehend whatever they are undertaking. Prabhu (1987) noted that there are three types of gaps; information gap, reasoning gap, and opinion gap. Information gaps suggest that any task should have a space or blank to be completed by the learner, through decoding or encoding information. For instance, a pair or a group of participants can be given a tabular representation to complete in the form of text. A reasoning-gap allows learners to infer, deduce, or identify the perception of relationship or patterns in a piece of information (Prabhu, 1987). The opinion gap establishes and articulates personal preferences, attitudes, or temperament to apply to a given experience. This may be attained through factual information or by stimulating an argument where an individual has to justify their opinion. In general, Prabhu (1987) feels that any task that meets this criterion is effective in learning the target language. Al Nashash (2006) examined the impact of a task-based program for developing the productive skills of the first-year secondary grade female students at a secondary school in Amman. The findings indicated that task-based language teaching through the designed program based on the procedures and principles of TBLT enhanced the productive skills of the participants better than the traditional method of teaching.

Experimental background
Aliakbari and Mohsennejad (2014) examined the effect of story retelling opinion-gap task on the enhancing speaking ability of Iranian EFL learners. For this purpose, 29 participants from a private language institute in Khorram Abad, Iran, were selected. The selected participants were divided into two homogeneous groups. The participants of the experimental group received activities through opinion-gap tasks while the control group received the traditional tasks. After that, the researchers gave a post-test of speaking to determine the effectiveness of the treatment on speaking skill of the participants. The findings of independent and paired samples t-test showed that the experimental group outperformed the control group on the post-test.
In another study, Fallahi et al. (2015) inspected the impacts of information-gap and opinion-gap tasks on developing Iranian EFL learners' reading comprehension. To do this study, three intact groups were selected, and they were randomly divided into a control group and two experimental groups. The experimental groups received the treatment by using two different tasks while the control group received question-answer activity. The results of One-Way ANOVA indicated the superiority of the experimental groups to the control group, and task-based instruction assisted to improve reading comprehension. Sarıcoban and Karakurt (2016) conducted a study to improve EFL learners' English listening and speaking skills at a State University in Turkey, School of Foreign Languages, Department of Basic English B1 and B1+ groups through task-based activities. The participants were 56 Turkish students. The instruments used for collecting data were 16 lesson plans and the speaking and listening quiz results as post-tests. After the implementation and the post-tests, the participants' opinions about the tasks were gathered as an interview. The findings of the research indicated that B1 groups did not get significant results from listening test and get nearly significant scores from speaking test while then listening and speaking results of B1+ groups through task-based learning after the implementations were highly significant, which indicates that their participation in the task-based activities in the classroom reflected the results positively. Also, the participants' opinions about task-based learning and teaching activities were, respectively, positive.
Rabbanifar and Mall-Amiri (2017) investigated the impacts of opinion-gap and reasoning-gap tasks on complexity, fluency, and accuracy of EFL learners' speaking. To conduct this study, 60 intermediate respondents from Iran-Australia English Institute located in Iran were selected. Then, they were assigned to two experimental groups, each group comprising 30 participants. The first group received the opinion-gap instruction, and the second group received reasoning-gap intervention. The speaking test was administered after 20 sessions of instructions. The results of One-way MANOVA indicated that reasoning-gap task had a significant effect on learners' speaking complexity and accuracy but not on fluency, in comparison to opinion-gap task.
After reviewing the related literature, it was discovered that some researchers conducted some studies to examine the effects of opinion-gap, information-gap, and reasoning-gap tasks separately and some studies compared the effectiveness of two of these tasks. No studies have compared the impacts of opinion-gap, information-gap, and reasoning-gap tasks to see which one is more effective on speaking skill. Therefore, this research aimed at comparing the effects of opinion-gap, information-gap, and reasoning-gap tasks on Iranian EFL learners' speaking fluency.
Based on the literature reviewed above, task-based instruction can be effective to improve students' speaking skill. In spite of its effectiveness, in Iranian EFL context task-based instruction has not been widely used. In Iranian EFL context, there are not enough facilities to implement task-based instruction. So, this study examined the effectiveness of task-based instruction on Iranian EFL learners' speaking fluency to pave the way for further studies.
Based on the researchers' best knowledge, doing studies on task-based instruction is of utmost importance in EFL context in general and in Iranian context in particular since Iranian EFL learners do not access to authentic situations to learn English language in group, instead they learn language individually. Learning through different tasks may compensate the lack of access to authentic situations. Performing tasks can engage EFL learners in language learning and also doing tasks can familiarize Iranian EFL learners with task-based learning.

Research question
The present study is designed to answer the following question: RQ: Among the three tasks (opinion-gap, reasoning-gap, and information-gap) proposed by Prabhu (1987), which one has more significant effect on improving Iranian EFL learners' speaking fluency?

Significance of the study
This study will shed light on the implementation of task-based instruction in teaching speaking in Iranian EFL context. This study hopes to be a guiding tool for further research studies which include task-based instruction in the context of Iran. Nonetheless, this study also looks forward to getting the attention of the language teachers, especially English, to make them think about a different way of teaching language rather than the traditional ones in their classrooms.

Participants
The participants of this study were 140 Iranian EFL learners who were selected among 168 students who were studying in two private English language institutes. They were selected based on Power analysis (Power analysis is an important aspect of experimental design. It allows us to determine the sample size required to detect an effect of a given size with a given degree of confidence. Conversely, it allows us to determine the probability of detecting an effect of a given size with a given level of confidence, under sample size constraints. If the probability is unacceptably low, we would be wise to alter or abandon the experiment); To make sure the learners constituted a sample homogeneous in terms of overall language proficiency, an Oxford Quick Placement Test (OQPT) was administered, and based on the results obtained from this test, 140 intermediate EFL learners were recruited as the participants of this study. All the participants were male learners with the age range of 15 to 18. The selected participants were divided into three experimental groups and one control group based on matched-subjects design (also called matched-group design), which is one type of experimental design in which the subjects are matched on some variable that might be affecting the dependent variable (in this case their language proficiency scores) and then split into two or more groups (in this case the four groups of the study). It should be noted that the ethical consent forms were also considered and obtained from the participants.

Instruments
The first instrument which was used in the present investigation to homogenize the participants' level of proficiency was the OQPT. According to this test, the learners who scored between one standard deviation (SD) above and one SD below the mean were determined as intermediate and were chosen as the target participants of the study.
The second instrument which was used in this study was a researcher-made speaking pre-test. The pre-test included several questions concerned with the learners' textbook (i.e., Top Notch 3). The participants were asked to talk about the topics of the units about 2 to 3 minutes, and their speech was recorded for the second rater. To ascertain the validity of the speaking test (which was held in the form of an interview), several steps were taken. First, the topic (for speaking) was selected from the topics covered in the book participants were studying as part of their regular institute course. Second, the topics/questions were given to three experienced teachers to check their suitability for use with the targeted participants. Besides, the reliability of the speaking test scores was confirmed by conducting inter-rater reliability by means of Pearson correlation analysis (r = .82). It should be noted the post-test resembled the pre-test of the study in as many respects as possible.
The mentioned tests (pre-test & post-test) received some reliability and validity measures. After construction, it was examined by 10 experts for its face and content validity. That is, to get sure about the Content Validity Index (CVI) of the test items, 10 teachers who also taught English for more than 5 years read through the tests and made some changes regarding the clarity, simplicity and the representativeness of items. Subsequently, the test was modified and then piloted on a similar group in another institute whose course book and level were the same. After applying validation and piloting, the necessary changes and modifications to achieve item characteristics (i.e., item facility, item discrimination, and choice distribution) were made to the test some items were considered inappropriate and omitted. The reliability of the pre-test and post-test was computed through the application of Pearson correlation analysis formula and values of 0.82 and 0.89 were obtained, respectively.
The last instrument used in this study was the speaking checklist (Hughes, 2003). It was used to help the raters score the participants' speech. The raters scored the participants' speech based on this speaking checklist.
In this study, fluency was operationally defined as the obtained scores of the participants on the speaking section of a PET. Their scores in fluency are determined by the Discourse Management Criterion of the Assembling Speaking Performance, as it is best matched with Ellis's (2004) description of fluency which comprises five points of the overall score. The Discourse Management Criterion includes the following issues; Producing extended stretches of language despite some hesitation, relevant contributions despite repetition, and using a range of cohesive advice. Four factors were analyzed to determine the fluency level of students. These factors were used in different previous studies on speaking fluency (Breiner-Sanders, Lowe, Miles, & Swender, 2000;Chambers, 1997;Rouhi & Marefat, 2006;Skehan & Foster, 1999;Tavakoli & Foster, 2008) which include: 1) The number of utterances that are abandoned before being complete (false starts); 2) The number of repetitions of words, phrases, or clauses (repetitions); 3) The number of lexico-syntactic repairs or reformulations for correction (reformations); 4) The number of lexical items that are substituted for another (replacement). In this way, higher measures show higher dysfluency, so following Huffman (2009), all dysfluency measures are subtracted from 20 to obtain fluency measures. Consequently, the range of fluency measure is between 0 and 20.
The rating scale which was used to rate the speaking section was taken from the University of Cambridge Preliminary Examinations paper. In order to ensure the accuracy of scoring, the researchers asked two of their colleagues, holding MA in TEFL with 20 years' experience of teaching and shared almost similar background in terms of qualifications and teaching experience to score speaking tests along with the researchers themselves. It is also important to mention that the score of each participant would be the average of the two raters.

Data collection procedure
In the first step, 140 intermediate participants were chosen as the sample of the study. After selecting the target participants, they were divided into three experimental groups including opinion-gap group, reasoning-gap group, information-gap group, and one control group. Afterward, a researcher-made speaking pre-test was administered to all the groups. Consequently, the intervention commenced.
In the opinion-gap group, the participants were given a topic and then they had pre-task phase activity in which they talked about the related words, structures or idioms about the topic to be discussed, and in "during task phase" there was an opinion-gap task; they had a discussion in which they exchanged their opinions, feelings, preferences, etc., about the topic they had been given. The teacher usually attempted to listen to what they discussed and tried to aid them to solve their grammatical problems and tell them the words they needed and played an important role in continuing their discussion. In the information-gap group, the participants were given a task to be discussed in the group; the participants, in pairs, discussed the task assigned to them. In the reasoning-gap group, the students were given a topic in each session, and they were required to provide reasons while speaking about the target topic. It is vital to mention that the topics were parallel in terms of complexity because they were checked and confirmed and validated by five English experts. Moreover, the selected topics were piloted. The participants of the control group, on the other hand, received the traditional instruction, the instruction of the control was teacher-centered and the participants did not have opportunities to give their opinions or reasons to do a task. After 15 sessions, when the intervention came to end, a speaking post-test was administered to the participants of all groups to determine the effectiveness of the treatment in their speaking fluency.
Regarding analyzing the students' fluency, learners' speech was transcribed, and the words in each transcript (before and after the teaching) were counted. This word count helped in assessing how learners improved their speaking fluency in terms of speed of production. Because the speed of production may not always guarantee comprehensibility, learners' transcripts were assessed in terms of grammatical accuracy. The comparison of word counts and the assessment of grammatical accuracy provided some insights into how learners improved in terms of their speaking fluency.

Data analysis
The collected data through the above-stated instruments were analyzed and interpreted according to the objectives of the study. Firstly, in order to check the normality of the data, Kolmogorov-Smirnov (K-S) test was applied. Then, statistical tools including one-way ANOVA and paired samples t-test were run to measure the impacts of the treatment on speaking fluency of the participants.

Results
As Table 1 indicates, the distribution of scores is normal in the pre and post-tests, therefore, to find answer for the research question, One-Way ANOVA and paired samples t-test which are parametric statistics were used.
Based on the descriptive statistics in Table 2, all the four groups' performances in the speaking pre-test were almost the same; their mean scores show that they were at the same speaking proficiency level before receiving the treatment. The mean score of the control group is 10.21, and the mean of opinion-gap group, reasoning-gap group, and information-gap group are 10.52, 10.11, and 10.35, respectively. Table 3 shows the scores of the four groups on the pre-test. Since Sig (.727) is greater than (0.05), the difference between the groups is not significant at (p < 0.05). In fact, they performed the same on the pre-test.
Based on the descriptive statistics in Table 4, the mean score of the control group is 10.31, and the mean of opinion-gap group, reasoning-gap group, and information-gap group are 17.08, 17.14, and 19.25, respectively. It seems that the experimental groups outperformed the control group on the post-test. Table 5 displays the scores of the four groups on the post-test. Since Sig (.000) is less than (0.50), the difference between the groups is significant at (p < 0.05). It can be concluded that the experimental groups outperformed the control group on the post-test. To see the exact difference between the groups, that is, to clarify which group outperformed other groups in the post-test, the  post-hoc Scheffe test was conducted to compare the specific mean effectiveness among the groups. Data are illustrated in Table 6.
Post-hoc comparison using Scheffe test indicated that the mean score of information-gap task group (M = 19.2567) was significantly different from opinion-gap task group (M = 17.0857), reasoning-gap task group (M = 17.1429), and control group (M = 10.3143). There was not, however, a significant difference between opinion-gap task group and reasoning-gap task group (P = .999 > .05). Paired-sample t-test was also run to find any possible significant differences in the participants' speaking fluency scores before and after the treatment (Table 7). Figure 1 shows the scores of all groups on the post-test. As it can be seen clearly, the information-gap task group performed better than other two experimental groups on the post-test but all the experimental groups outperformed the control group. In Table 7, four paired samples t-tests were used to compare the pre and post-tests of each group. The difference between the pre-test and post-test of the control group is not significant since Sig (.126) is greater than 0.05. The difference between the pre-test and post-tests of the three experimental groups is significant since Sig (.000) is less than 0.05. Therefore, it can be concluded that the treatment had positive effects on speaking fluency of this group.

Discussion
In this part the research question "Among the three tasks (opinion-gap, reasoning-gap, and information-gap) proposed by Prabhu (1987), which one has more significant effect on improving Iranian EFL learners' speaking fluency?" is answered based on the results obtained in the tables above. The findings revealed that the participants of the experimental groups who received taskbased instruction (opinion-gap, reasoning-gap, and information-gap) outperformed those who were trained through traditional instruction (control group). The findings also indicated that among the three mentioned tasks, the information-gap tasks had more effect on speaking fluency of EFL learners.
As it can be seen by the data at hand, the instruction which was done by the tasks (opinion-gap, reasoning-gap, and information-gap) had a significant impact on students' performance. Through doing the tasks mentioned, the participants were involved in learning and this involvement could help the participants to enhance their speaking fluency. In information-gap task group, the participants exchanged pieces of information to complete a task together, in opinion-gap task group, the participants stated their personal preferences, attitudes, and feelings to complete the  given tasks, in reasoning-gap task group, the participants were required to derive some new information by inferring it from information they have been given. The activities mentioned can be the reason of the participants' speaking fluency improvement.
Tasks can supply students plenty of opportunities to utilize language in the classroom without feeling fear of making mistakes. Tasks provide the opportunity for "natural" learning within the classroom context, and they contribute to the improvement of communicative fluency while not disregarding accuracy (Ellis, 2009). Tasks also can boost motivation and self-confidence as well as sub-skills of the students (Nunan, 2006). Information-gap activities promote cooperative learning, give the opportunity to work on negotiating meaning, enable leaners to feel comfortable to speak, increase communicative practice maximally, enable students to communicate intended meaning, and make students to pay heed to the social context of the communicative events (Prabhu, 1987).
The findings of this study lend support to the previous findings, e.g., Aliakbari and Mohsennejad (2014), Fallahi et al. (2015), and Rabbanifar and Mall-Amiri (2017) who confirmed the effectiveness of opinion-gap, reasoning-gap, and information-gap tasks on improving different skills of English language.
In addition, the results of this study are supported by Marzban and Hashemi (2013) who examine the impact of opinion-gap task on the speaking ability of Iranian intermediate EFL learners. The participants in the experimental group received the treatment through opinion-gap task while the control group received the traditional instruction. An oral interview was utilized both as the pre-test and post-test. The findings uncovered that opinion-gap task improved Iranian intermediate EFL learners speaking ability.
It should be noted that task-based learning has its own problems. For example, abstract tasks like expressing an opinion where the elements of the task are concrete can be more difficult. Nunan and Keobke (1995) conducted a study with 35 undergraduate students by using various reading, listening and speaking tasks and asked the students how difficult the tasks were and why. The learners in the study pointed out that lack of familiarity with task types, confusion over the purpose of the task, and the impact and extent of cultural knowledge are the predominant factors that cause Task difficulty.
Though the researchers found that task-based learning was effective for speaking fluency of Iranian EFL learners, they directly observed that task-based learning was not suitable for teaching all topics and also some students did not enjoy learning based on task-based learning. In fact, some tasks were difficult for the students to do. In addition, tasks need to be done in authentic situations but in EFL contexts finding authentic situations is not possible. It is recommended that the English teachers and researchers provide near-authentic situations for the students to be able to do different tasks successfully.
To put it in a nutshell, the researchers believe that the information-gap tasks might be more effective for intermediate learners as they have more language and world knowledge than the low-proficiency learners to discuss the controversial issues, and it can be concluded that these tasks could be helpful for the learners who are motivated and not shy to have discussion about their feelings, preferences, and their ideas.
To sum up, after applying information-gap activities in speaking class for eight meetings, it can be concluded that information-gap activities can better improve the students' interaction with the teacher and other students. When they were practicing in pair work and group work, all of them participated. It meant that students' participation in the class also improved. On the other hand, they decreased the amount of teacher talking time. Moreover, information-gap activities can maximize students' opportunities to speak during the English lesson and provide the potential benefits of student-student interaction. In order to elicit information and opinions from the teacher and friends, the students needed to interact among them. They should spend most of the time working in pairs and groups. The students have reasons to interact and tasks to fulfill. Information-gap activities encourage students' practice opportunities of the target language receptivity in the lessons as a result of presenting various tasks. In the light of students' reflections for the tasks used during the study, which were very positive, it showed that students were receptive to the idea of information-gap activities while learning English. Translating all the ideas of the findings into the framework of improvement, all language teachers are invited to become familiar with information-gap activities which are a very popular and adaptable framework in communicative language teaching. When adopting this framework, language teachers should provide their students with a variety of enjoyable tasks. In conclusion, the results of this study showed us how important it is to use activities that encourage speaking. Information gap is highly proved as one of the activities that enhance the oral proficiency of the students.
As there is no perfect in this world, this media is not perfect. Besides those advantages, information gap also has some disadvantages such as: 1. Information gap consumes much time to do or conduct.
2. Information gap demands teachers to be skillful in controlling the class.
3. The students are sometimes lazy to do the teacher's task and feel confused in saying the expressions what they want to say in the task.

Conclusion
In brief, implementing different tasks (opinion-gap, reasoning-gap, and information-gap) in the language classroom can subject EFL learners to near-authentic language use. Based on the obtained outcomes, the speaking fluency of EFL learners tends to enhance through exposure to task-based inputs. Through performing different tasks, EFL learners have more language input and as a result, they have more output. That is, they try to use their language knowledge to transfer their intentions so they get more fluent in speaking. As a result of doing the tasks, the participants of the experimental group could benefit from their partners' language input which was useful for improving their speaking fluency.
This study can have some implications for EFL teachers, learners, and material designers. The findings of the present research can encourage English teachers to use task-based instruction in their classrooms and require the students to perform different tasks in order to learn English language more easily. Through doing tasks, teachers can encourage cooperative learning rather than competitive learning. Moreover, the English teacher should take some strategies to develop the students' motivation and effort in learning English and also find the most appropriate technique to build an effective and cheerful atmosphere of learning environment. Besides that, the English teacher should pay attention most on teaching speaking because it is one of the important skills that helps students in mastering English. Moreover, teacher should control their students to do a lot of practice in and out of the class.
Through doing different tasks in different situations, EFL learners can master English language in general and speaking skill in particular. The findings of the present study can make the syllabus designers aware of the importance of using task-based instruction in learning and teaching English language. Syllabus designers can incorporate task-oriented activities and exercises in EFL textbooks in order to encourage EFL learners to learn language by doing the tasks, in fact, "learning by doing" can be encouraged by the results of this study. The findings of this study can enrich the literature related to the tasks and speaking fluency. Therefore, this study can pave the way for the next researchers.
Like any other study, this study also has a number of limitations, some of which could influence the findings and restrict the generalizability of the results. Firstly, in the present study, the number of participants were limited to 140 students. However, working with bigger groups is more difficult and time-consuming. Secondly, only one level (intermediate) of English students were participated in this study. Thirdly, only male students were included in this study; therefore,; the results may not be generalizable to the female students. Fourthly, only 15 to 18 years old students were included in this study.