Mobile-based aural oral skill lessons: The effects on EFL teacher trainees’ oral performance

Abstract EFL teacher-educators and teachers are seen as ignorant of teaching aural skills for referring to resource shortages is a common mechanism for their scapegoating. It hinders students’ opportunity to boost oral proficiency in the abundance of their smartphones in the classrooms to learn aural and oral skills. Hence, Moodle 3.0, a learning application, was used to create and deliver aural comprehension lessons by customizing audiovisual texts on social media to practice oral skills. A one-group-only quasi-experimental, Interrupted Time Series Design was employed to investigate the effect of mobile-based aural comprehension lessons on the general and specific oral skills’ performances of the preservice teacher trainees at Arba Minch Teacher Education College in Ethiopia. A total of 25 trainees of the 3-year diploma program were taken comprehensively as samples. To analyze data quantitatively, in addition to descriptive methods, Kruskal-Wallis, and Wilcoxson’s Signed Rank Tests were run to inferentially determine the significance of differences in the effects across the oral sub-skills and on the trainees’ general oral performance, respectively. Thus, the results disclosed that mobile-based aural oral skill lessons had positive significance in the trainees’ general oral performance without significant differences in the effects in performance across the oral sub-skills. Finally, the researchers recommended others to investigate and minimize first language interference and pronunciation problems of EFL learners. The EFL teacher trainees’ learning styles should also be further studied to understand the effect of mobile-based aural-oral skill lessons on their EFL learning/studying habits after the exposure to mobile-based lessons.


PUBLIC INTEREST STATEMENT
In the contexts of Arba Minch Teacher Education College, student mobile phones are the only widely available technological devices that can be used for educating them if proper attentions are given to embed in the English language instructions. But currently the teacher trainees are simply taught what are on the internet adopted written materials instead of having a direct exposure to learn with audiovisual materials on their mobile phones. Moreover, the teacher educators use to ignore teaching aural skills due to the lack of focus and classroom situated instructional technologies even though aural skill is thought by many EFL scholars the greatest input provider for the learner oral skill developments. Accordingly, the graduates of teacher education colleges do not acquire sufficient oral skills to communicate in the English language in their daily lives and to teach the language in the language. In the EFL classrooms, they are frequently observed to switching the code to their mother tongues as a result. The study tackles these problems.

Introduction
The lack of students' aural skill experience seems to highly affect students' oral skill developments more than any other skills in English as a Foreign Language Learning (EFLL) because of the natural connection between the two macro skills. It is theoretically accepted and practically observed that a high-level aural efficacy leads to an acquisition of high-level speaking efficacy. Rocío (2012) acknowledged the significance of teaching aural and oral skills together to promote perfect L2 learning by stressing the necessity of integrating the rest skills later. However, EFL teachers often ignore teaching aural skills which in return is a hindrance to students' verbal communication efficiency in the abundance of teacher trainees' smartphones in the EFL classrooms to access authentic listening resources online. Underwood (1989) and Shian and Yunus (2016) witnessed the teaching of aural skills has been forgotten by most EFL teachers as is now the case with teachers in Ethiopia.
Until now, teaching aural skills has not received better attention compared with its practices in the remote past. As a result, there is a high tendency for students to experience limitations to speak in the target foreign languages. For instance, we may try hard to help students be good speakers of the English language, but in the first place, without teaching a student to be able to effectively listen to what is said and know how it is said, expecting him/her for efficient oral communication in the target language would be resulting insufficient oral improvements, perturbed teacher satisfactions and frequent communication breakdowns. In this regard, teaching aural comprehension skills should be followed by teaching oral skills because, in addition to learning how words pronounced, communicative listening demands giving appropriate verbal responses during interlocutions in the real world so that response is a stage of listening and is the final listening process requiring verbal involvement of the listener (Nunan, 2001;Rivers, 1966;Rocío, 2012). It is the sixth stage where a listener gives appropriate feedback to the speaker in some way and confirms that the message received is accurately understood plus understanding accompanying nonverbal clues signifying the end of the aural comprehension process.
Theoretically, a good listener becomes a good speaker (Lynch, 1996). In communication to existing between two people, a listener must listen to and respond to what the first speaker says. Therefore, teaching aural skills or listening should be one of the prime targets of EFL instructions to promote the students' speaking competence, specifically in the contexts where they do not get a chance to practice aural-oral skills in the target language away from their classrooms. Generally, helping students speak a foreign language should base teaching first to enable them to listen to the target language well. Postovsky (1976) as noted by Rocío (2012) explained that speaking develops mainly based on the individual's potential to listen to verbal information with maximum comprehension; therefore, automaticity of speaking proficiency development is very likely to depend on the frequency and adequacy of the aural exposure, and it reveals itself by the student's faster-oral performance changes.
In classrooms where lack of technology-based infrastructure is a commonly observed instructional problem, adherence to employing mobile-based lessons may "increase teachers' creativity in designing teaching materials and media, increases students' learning motivation, mobility, accessibility, and excellent potential for providing students with the learning materials whenever and wherever" (Elfiona et al., 2019, p. 1). Accordingly, aural skill instruction and choice of learning materials should consider learners' current level of aural comprehension performance and their past experiences of listening in the target language. Activities should also be motivating enough to inspire them for self-directed, independent, real-life aural and oral communication experiences elsewhere. Hwang et al. (2014) stated the positive effect of mobile-based learning on the perception and intentions is to get into activities being motivated to practice the English language skills more and more using the approach. Therefore, aural comprehension lessons designed by classroom teachers should include language models for students to engage in, practice, and fulfill their real-world communicative needs.
Similarly, as aural skills instruction aims to make students effective communicators in real-life contexts, material authenticity must be paid attention to. Rocío (2012) says thinking about the way how we listen in real life when we deal with aural skill instructions in classrooms is the best option; in such a way, teachers can provide students the chance to actively listen to authentic texts that consist of a variety of English speakers' accents, varied and useable contents, as well as situations in which students could apply in the real world. Likewise, by Vygotsky's assimilationist and accommodationist theory, a good aural skills lesson leads the learner to exploit the newly acquired language skills (by attending to new speaking styles and oral expressions) in situations where s/he is expected to engage verbally. Concomitantly, Krashen and Terrel (1983) claimed that input hypothesis, the provision of a comprehensible new input (i + 1), has something to do with in adding new mobile-based aural oral skill lessons to be rehearsed and immediately exploited as the students try to speak them out in the way the new language lesson or item was practiced in the learning context when a need arises in a new communicative situation.
Frequently remarked that mobile-based learning is still at its infancy. Chunga et al. (2019) reported the most mobile-based lessons for which activities were designed based on school curriculums engaging students in the real world. However, most past studies on language teaching and learning indicated that most require learners to read from mobile phones rather than to search for audio and audiovisual materials (Azeez & Bajalani, 2018). Hsu et al. (2013) complementarily described the different types of display modes and video captions on mobile devices as having significant positive effects on the students' English language comprehension and vocabulary acquisition.
Currently, EFL instructions ignored the significance of first teaching the listening skills cannot make the learners be efficient speakers of the target foreign language. Everyone can imagine how technology plays a significant role in the realization of the CLT approach (Communicative Language Teaching) that is also pillared in the Ethiopian EFL teacher training programs and school curriculums even if MALL is not duly acknowledged to integrate it into the education system. Concerning learners' interests, most of the time, they prioritize and focus on developing their oral communication efficiency; therefore, as described in Valette (1977), they should be given opportunities to listen and speak the target language and take part in meaningful communicative interactions. Doubtlessly, this calls for shifting the teaching role to a student in the mobile embedded English language teaching. Similarly, the shift alters the realities of traditional language teaching, and EFL learners are encouraged to engage in different communicative situations that urge them to produce comprehensible oral discourses (Yoon, 2015). Therefore, there will be a need to train teachers using evidence-based strategies to enhance their skills in teaching aural comprehension lessons (Chang, 2018).
One of the striking strategies to integrate speaking lessons into the technology-embedded aural skills instruction is to pay attention to post-listening activities. Post-listening activities that usually mark the end of the listening instruction are also used as means to assess and evaluate learning outcomes (Gilakjani & Ahmadi, 2011) could be mainly through the follow-up questions, oral responses and reports, peer feedback, discussions, and dialogues taking place based on the listening texts they are exposed to listen to and complete activities following them. Therefore, "mobile-based lessons can be a solution to solve various problems encountered in teaching and learning to listen" (Elfiona et al., 2019, p. 1).
However, m-learning involves any portable learning material usages such as audiobooks, audio cassettes, CD-ROMs, and any radio and DVD player (Azar & Nasiri, 2014). But mobile phones with smart features substitute these tools and even advance all the functionalities of big computers. As a result, students must be encouraged to search, share and use audiovisual materials on their mobile phones. TV and other electronic media simultaneously transmit audio and visual presentations and should be taken as pedagogical technologies in addition to valuing them as entertainment objects. Like TV, a mobile phone will provide a variety of national and international news broadcasts through audiovisual modalities and may acquaint learners with foreign language structures, vocabularies, intonation and stress patterns, word rhymes (in songs and poems), and advanced and lengthened discourses to attend and practice aural and oral skills in the target language having a relatively greater degree of fluency, accuracy, and precision. In the English classroom, according to Yükselir and Kömür (2017), the use of audiovisuals from online sources allows students a chance to interact and properly communicate information in the language and develop their linguistic competence for which mobile phones are seen as an incredibly dependable means of access to free downloadable texts using the WIFI which never cost them, their teachers and the respective institution much.
Mobile built-in features and applications could be taken as the tools possibly helping learners enhance their speaking skills in the MALL environments (Rajendran & Yunus, 2021;Saidouni, 2019). For example, Read and Kukulska-Hulme (2015) conferred that Audio News Trainer (ANT) mobile application stimulates skill development and practice. Furthermore, Ebadijalal and Yousofi (2021) found oral peer feedback positively influences students' oral performance in terms of selfconfidence, willingness to communicate, risk-taking, engagement, and self-directed performance and as variables to be grown in the mobile blended learning environments. These micro-skills are solely attached to the psychological status of a learner in a conversation situation. But assessment lacked to consider sub-constructs skills reflecting an individual's verbal ability such as fluency, language control, use of vocabulary and structure (Content), and the inherent risk-taking subskills. Peng et al.'s (2021) review also acknowledged effectiveness of using mobile technologies for language learning even though they exposed some of the limitations of the studies done so far around mobile-based learning. Scarcity of rigorously designed MALL research on Communicative Language Teaching, the lack of focus on integrating aural and oral skills, and the absence of theory-driven MALL studies were the limitations of the review. Therefore, the current study intended to fill these gaps by applying constructivist mobile-based aural oral skill lessons as means to provide aurally comprehensible inputs (i + 1) and practice speaking in the English language with a focus at identifying the effects on the trainees' general oral performance and their performances in the oral micro-skills.

Null hypotheses (Ho)
The following are the null hypotheses: (1) Ho: There is no significant effect of mobile-based aural oral skill lessons on teacher trainees' performance in the oral subskills after receiving mobile-based aural oral skill lessons.
(2) Ho: The difference in the effects of mobile-based aural oral skill lessons on teacher trainees' oral performance across the subskills is not significant after receiving mobile-based aural oral skill lessons.
(3) Ho: There is no significant effect of mobile-based aural oral skill lessons on teacher trainees' general oral performance after the trainees' participations in the mobile-based aural oral skill lessons.

Overview
In human communication, listening receives the largest share of time when compared with the time spent on communication using other skills. Listening is also a conscious act of attending to verbal information to get meaning out of stretches of speech. Lindsay and Knight (2006) described the different alternative situations and activities in which we engage ourselves by listening for personal and social reasons, in different ways, and in different settings. Listening may occur when attending a speech face-to-face or on the telephone, record, dialogue, discussion, announcement, weather forecast, play, music, lectures, professional advice, instruction, direction, and being eavesdropper, etc. Therefore, the aim of aural skills instruction should be to enable learners to be effective listeners of a variety of speakers for a variety of purposes and in a variety of listening situations. Teachers are also encouraged to focus on student language learning enjoyment through technology application. By the same token, aural comprehension activities require technical support to run lessons and make activities more interesting and enjoyable (Bashori et al., 2021). Here comes the inevitability of using a mobile phone to assist a student's learning and engagement in aural skill instructions especially to be delivered in the EFL classroom settings where a shortage of instructional technology infrastructure is apparent. Likewise, Traore and Kyei-Blankso (2011, as cited in Liu & He, 2014) described MALL as having positive effects on students' development of literacy and language skills by inspiring them to be engaged in learning in their own ways by promoting self-led learning Theoretically, listening is taken as the most important but essential skill based on which the other skills (speaking, reading, and writing) are to be mastered easily. Rocío (2012) remarked significance of teaching listening and speaking skills together to promote a perfect L2 (Second Language) acquisition by acknowledging the necessity of integrating the rest skills later on since learners mostly give priority to developing their oral communicative efficiency so that they should be given opportunities to take part in meaningful communicative interactions (Valette, 1977). Ebadijalal and Yousofi (2021) also found that oral peer feedback positively influenced students' oral performance. Similarly, Traore and Kyei-Blankson (2011, as cited in Liu & He, 2014) described MALL as having positive effects on students' development of literacy skills (reading and writing) and promoting self-led learning.
The integration and utilization of emerging digital technologies for instructional reasons has been becoming a global trend towards the end of the twentieth century. Gangaiamaran and Pasupathi (2017) suggested the possible conditions for using a variety of computer gadgets to implement in-MALL courses, e.g., smartphones, tablets, laptops, and iPad. However, Schoepp (2002) adds that technology currently plays a significant role in EFL teaching, for it offers a wide variety of language learning resources. Nevertheless, Computer Assisted Language Learning (CALL) has brought tremendous breakthroughs in learning, changing the role of the teacher to students (Boulton, 2009). Parallelly, technology holds exciting promises to make education malleable and convenient, allowing students of all economic levels to participate. Research evidenced that mobile technology is a feasible means to teach listening skills (Adams, 2012).

Embedding mobile phone in the aural-oral skills instruction
In resourceless English as a Foreign Language classroom where students are expected only to listen to their teacher's voice, a listening lesson should embed mobile phone technology to present aural contents and comprehension activities followed by oral discussions and reflective feedback to promote their aural and oral skill performances. Teachers' efforts to enhance student engagement and control of listening lessons should regard the accessibility of mobile devices in the classroom and their applicability as a technology to teach and learn EFL (Carmody & Presser, 2018). They also stressed paying attention to Nearpod to deliver language lessons and see the effects as a consequence.
Among the four language skills, listening is the most difficult but is the most necessary skill for oral communicative competence brought by the individual learners. Teaching listening skills in foreign language contexts only through teacher voices and records of their voice is a tiresome activity. Similarly, bringing a CD or DVD player to classrooms on a regular basis is also an unlikely occurrence to persist, exhausting, and old-trended audiolingual fashion. As a result, teaching listening as a skill receives the attention that is highly less than the attention given to teaching the other skills. In contrast, the inclusion of mobile phones, in particular, is suggested and could be thought a useful way to develop vocabulary skills that are necessary for increased EFL learner speaking proficiency progress (Khan et al., 2018). Moreover, listening is often said a passive skill, and the learners are seemingly simply sitting quietly and become idle in attending to verbal information. Elfiona et al. (2019) stated listening skill is ignored even in the high schools' curriculum of Padang for the reason that there are limitations of media technology, opportunities to practice EFL listening, and preparation of appropriate listening texts, while the obvious learner difficulty to determine appropriate listening materials for themselves is among the baldly noticeable instructional problems.
Chunga, et al. (2019) say a review of most experimental studies that were published in the years between 2010 and 2016 revealed that most mobile-based lessons engaged students in the real world for which activities were designed based on school curriculums. It is believed that any form of instructional activity that is attached to learners' real-life experiences and needs has used to be given great acceptance and when viewed in light of the contemporary educational theory, constructivism. Considering learners' attachment with the mobile phone and their nearness to social media through which they best know their world, building their knowledge of the self, the world around them, and beyond is so significant as far as integration of mobile phones in English as a Foreign Language and aural oral skill lessons is concerned. In addition to this, social media is currently considered the most striking treasure house for authentic foreign language teaching and learning materials. Read and Kukulska-Hulme (2015) have given a detailed explanation of the importance of focusing on teaching listening comprehension skills to language students. In their account, they also described the benefits of using mobile apps to stimulate practice by attaching the potential of social media-based tools for interactions in second/foreign language learning.

Instructional stages and the aural-oral skill lessons/activities
Activities are one of the means in the realization of the attainment of learning outcomes. Without fabulously designed learning activities, a language classroom will dry out. In other words, students may not be actively engaged in the learning process or become passive recipients of information in classrooms where the teacher is perceived as an omnipotent person, director, controller, and talking the whole period and is a clear revelation to traditional language teaching classroom. However, several experimental studies on MALL indicate that mobile-based activities are liable to engage students in the learning process by offering real-world tasks and situations (Chunga et al., 2019). In the review, they concluded: . . . mobile devices were considered a main way of allowing students to acquire self-learning materials rather than only mediation learning across contexts. As the current studies can be considered to contain blended rather than purely self-paced learning, there is still a large space for mobile learning progress and development. (Chunga et al., 2019, p. 1) However, it is a frequently remarked idea that mobile-based learning is still in its infancy, and the theoretical fundamentals are under consideration. Likewise, most past studies in language teaching and learning areas required learners to read from mobile phones rather than search and listen to audio and audiovisual materials (Azeez & Bajalani, 2018). The teaching of listening as a skill is forgotten by most EFL teachers even though it is so difficult for their students to be independent learners and to be sure whether what they do with their mobile phones was supported by the school curriculum or not (Shian & Yunus, 2016). Therefore, the task of teachers should be cautious to select and adapt materials that fit with the instructional goals and needs of students at their best, for which the use of mobile apps, social media content, and educational platforms are the dominant preferences and are the prescribed means of addressing resource-related current challenges to execute aural comprehension practices and oral skills lessons. As a result, all resources teachers bring into classrooms, share with students, and uploaded on the online learning platforms to deliver aura oral skill lessons should be carefully chosen, adapted, sequenced, and graded ahead in ways that are consistent with listening activities to be executed in a conventional listening classroom and by keeping three instructional stages: pre, while and post-listening. Gilakjani andAhmadi (2011, as cited in Chang, 2018) illustrated the types of activities for listening comprehension instruction by classifying them into these stages. They explained the listening activities call for oral practice and demonstration of their comprehension skill focused on the postlistening session in the list below: (a) Evaluation activity • Developing students' self-evaluation

(b) Comprehension Activities
• Helping students check their understanding, interpreting the text (c) Production activities: • promoting students' oral ability through personalization and practice of the listening resource, • Doing problem-solving discussions (such as making Mini-PBL) • performing role-play written work for (oral) presentation, • interpreting listening (such as critical thinking), and using rubrics/criteria for self-assessment. Shian and Yunus's (2016) findings indicated that the ELT teachers found the audio clips helpful and convenient to teach for their pupils were seen as more interested and paid more attention during the listening sessions. The audio clips reported that they reinforced listening skill development; the study finally recommended that audio clips ought to be extensively used in the listening instruction by slowly moving towards exploiting authentic listening texts and real-world tasks with the help of social media. Similarly, Harris (n.d., p. 54) described "using video as a tool for developing listening skills can be motivating and interesting for students. By providing links to the videos online, students can watch again at home after class, if necessary." Hwang et al.'s (2014) study of the effects of mobile devices on English listening diversity and the speaking groups supported the preceding claim.

Mobile and the pedagogic soundness to deliver aural-oral skill lessons
Although technology is said to have a great role in promoting education in general, the structuring of technology-enhanced classroom realities may look different for mobile learning is a comparatively new occurrence and the theoretical fundamentals are presently under development (Chua1 et al., 2019). Thus, they considered pedagogical skills, situations, task content, continuous reflection, readiness, and native speakers as pivotal points for the adoption of a mobile-based approach to language learning. Therefore, in the design process, these important issues must be addressed in the aural oral skill lessons and be the heart of activity, and arranged stepwise from pre, to post-listening stages. For instance, Toland et al. (2016) devised a new method of oral presentation through posters as lessons aided by mobile video to give reflective feedback in activities that aimed at replacing the use of Microsoft PowerPoint Presentation software to practice giving a public speech that could often be felt anxiety-inducing, glorified reading or memorization exercise with text-heavy slides and often failed to meet the intended objective of developing the learners' presentation skills. Using a graphic presentation method, Robin (2016) established Educational Uses of Digital Storytelling, a website (http://digitalstorytelling.coe.uh.edu), to assist how digital storytelling could be integrated into a variety of educational activities and presented guidelines to apply it well in the EFL lessons.
Chunga et al. (2019) reviewed experimental studies on mobile-based learning in the activity theory framework and published them between 2010 and 2016. The review revealed that mobilebased learning, in which activities crave school curriculum embedment and link textbooks, engages learners in real-life situations. The review deduced that mobile phone plays beyond mediation roles because of its ubiquitous learning potential that gives the student the chance to acquire self-learning materials. Although current studies could be said they take into account a blending of language learning with a mobile-based approach, Chunga et al. (2019) concluded that there is still a gap to be filled and mobile-based learning to progress and achieved by explaining the existing high possibilities to conduct new studies on the effects of mobile-based approach in language learning. In general, the use of mobile phones as an instructional technology is a significant development. According to Baleghizadeh and Oladrostm, (n.d.) it has received considerable attention from students, teachers, and researchers in recent years; for example, they empirically recognized that EFL students' grammatical knowledge boosts through mobile phones. However, Burston (2014) said the attempts to apply MALL have been limited to pilot testing and predominantly restricted to be project plans (proposals), proof of concepts, and classroom interventions.
Constructivism is portrayed as a more natural, relevant, productive, and empowering framework to train students in teacher education (Cannella & Reiff, 1994). Thus, "As aptly stated, the key is to ensure that computer technologies are designed around learning theories and principles because they can then be effective in improving student learning" (Schacter & Fagnano, 1999 as cited in Schoepp, 2002). However, the trend of having exclusive ownership of instructional technologies strengthens the old practices to continue in the name of technology integration by reapplying traditional method of teaching that focuses on knowledge transmission by being ignorant of learner significant gains from the technology itself (Culp et al., 2005 as cited in Ottenbreit-Leftwich et al., 2010). Suhendi and Purwarno (2018) studied that constructivism has a positive impact on educational progress and contributes to improving students' abilities because it opens learners' curiosities to do or know about something new; therefore, they can also build their knowledge to create and design something related to their needs as per the constructivists' presuppositions, such as Piagetian and Vygotskian ideologies. Rajendran and Yunus's (2021) review of mobile-based empirical studies suggests that "the application of MALL propagates the concepts of constructivism theory, promotes a stress-free environment, supports situated learning, and provides ease of use." In addition to Piaget and Vygotskian's constructivist perspectives, the insight into SLA research of Krashen and Terrel (1983) is a tributarily significant basis to provide comprehensible input (i + 1) in the experimental interventions and balance individual differences among learners. Similarly, learner social interaction is being weighed by taking into account the learner Zone of Proximal Development (ZPD) and by grounding on teachers' relentless and unreserved scaffolding efforts to help their students' learning, in the case of this study, to reinforce aural comprehension-based oral skill development with the Technology (MALL). "This theory proposes importance to social interaction and emphasizes the role of language, communication and instruction to gain knowledge" (Owen & Razali, 2018;Vygotsky, 1978).
Similarly, students' speaking performance improved after communicative activities in the classroom (Owen & Razali, 2018). Therefore, being taken for a grant, the CLT approach realizes constructivist learning in EFL classrooms. Khan (2013) said that communicative language teaching incorporates the idea of interaction, considering it an essential element of the whole process and output. Peng et al. (2021) identified three variables contributing to making mobile-based learning more effective. These are the types of activities, modality of delivery, and duration of treatment. Even though CLT is a multi-faceted approach and provides methodical options for the implementer teacher to choose from, Richards (2006) proposed two fundamentally process-oriented CLT methods known as Content-Based Instruction (CBI) and Task-Based Instruction (TBI) that are presumably best enacted to attain the CLT goals as well as the goals of the current study through applying mobile-assisted aural and oral communicative activities. As a result, CBI and TBI activities were to be used to engage trainees while implementing the quasi-experimental studies in the CLT and Constructivist framework for a solid one semester. Within a constructivist learning framework, Harris (2015) says it is instructors' responsibility to encourage students to participate in the learning process and give them appropriate tools to work with the knowledge they discovered; thus, mobile phones provide a unique opportunity for learners to participate in the dynamic system they are learning.
Mobile-based aural-oral skill lessons were susceptible to changes in the teacher trainees' general and specific oral skill performances. Lackman (2010, p. 1) says, "By raising awareness of speaking subskills and providing classroom practice with them, we will be providing students with strategies to improve their communication outside the classroom, which is, or should be, the ultimate goal". We do not just make students speak about the subskills we should be teaching in classrooms, argued moreover. Khaizal et al. (2021) also analyzed previous studies and found four main themes in speaking subskills covering the aspects of pronunciation, fluency, speaking in the form of discourse, and spontaneously speaking. Similarly, an excerpt published by Binus University (2018) diagrammatically presented the four speaking micro-skills required to be a good speaker as shown here below in Figure 1.
Taken from The Four Speaking Skills. Binus University. Published at: 11 October 2018. https:// english.binus.ac.id/2018/10/11/the-four-speaking-skills/(Accessed on public internet) Therefore, the quasi-experimental study delivered mobile-assisted aural-oral lessons in the experimental interventions that lasted a semester. The training let teacher trainees have fluency, vocabulary, grammar, and pronunciation practice, and practice on further speaking micro-skill variables and tested in terms of their oral fluency, language control, content (vocabulary and grammar usage), and risk-taking abilities before and after the interventions.

Study design
The current study was typified as a quasi-experimental study in the design because it was educational research conducted in a natural setting and trained a non-randomly assigned only one experimental group of study subjects. Precisely, a group of trainees available in one section in the teachers' training ground trained as teachers of English language received a mobile based aural-oral skill training.
The current study employed a quasi-experimental Interrupted Time Series Design to evaluate whether mobile-based aural-oral skill lessons had effects on teacher trainees' general and specific areas of oral performance. Therefore, the study intended to deliver mobile-based aural comprehensible inputs to serve trainees participating in only one experimental group study. In the end, the effects of the lessons on their oral performances were to be identified after their participation in a semester of intervention training.  2005) say undertaking true experimental research becomes difficult since randomization to exposures is essential in conducting experiments. Besides, the first and foremost reason for using Time Serious designs in this quasi-experimental study was its deduction from the research objective and appropriateness of it to conduct the experiment on a solely available 25 graduating class teacher trainees in a single section without randomization. Therefore, it enabled the researcher to examine teacher trainees' attitudes to mobile-based lessons and aural-oral skill performance changes in the English language. Dornyei (2007) also says performance change in listening skills and in the variables (emotions or affective filters) related to listening skills are best observed and explained using true and quasi-experiments. However, it is unethical to undertake true experiments on human beings; thus, a quasi-experimental design was preferred to apply for the current study. Mackey and Gas (2005) Backed up with a positivist philosophical dressing up, the study highly relied on quantitative data manipulation to reveal the degree of the effects. As the study was aimed at investigating whether a mobile-based approach had significant effects on a single section of third-year English as a Foreign Language teacher trainees, the design presumably confided to be a Nonequivalent Comparison-Group Design and is amongst the most commonly employed experimental designs in this category (Marczyk, et al., 2005). Moreover, they said Multiple Time-Series Designs is the one under Nonequivalent Comparison-Group Designs that is quite similar to true experimental designs except for a nonrandom assignment of research subjects, "can be quite strong in terms of its ability to rule out other explanations for the observed effect." Therefore, the design exclusively used for this study was a Nonequivalent Comparison-Group Quasi-experimental Time Series research design which offered two alternative specific designs known as Interval Time Series and Interrupted Time Series Designs to choose from the nature and number of observations to be made.

Setting and participants
Participants in the study were EFL prospective teacher trainees at Arba Minch Teacher Education College in a diploma program to become primary school teachers in Ethiopia. A group of 25 (n = 25) graduating class teacher trainees in a preservice teacher training program chosen to participate in the study were the last batch to graduate before the termination of training teachers at the diploma level. A comprehensive sampling technique to choose them was employed as they were few in number and the last batch to graduate with a diploma as teachers in the primary schools in the country.

Data collection instruments and strategies
In order to determine whether a mobile-based lesson approach to attending aural-oral skill lessons affected the trainees' oral performance or not, the participants were given a semester of instructional treatments. Questions for the speaking tests were adapted from an excerpt entitled A Guide to Assess Speaking Performance "Speak Practice Test: General Directions." Accordingly, oral performance tests were conducted four times (OPreT1(O1), OPreT2(O2), OPostT1(O3), and OPostT2 (O4) Both the pre-tests and post-tests were administered twice before the intervention and twice after the intervention, respectively. These were to get accurate data about the trainees' true performance and enhance measurement precision. In addition to assignments of one evaluator to administer a test alone, the design helped test takers to demonstrate their actual performance once again if they missed the opportunity to perform well on the first test occasion, minimize scorer biases, predict interrater consistencies, and depend on average performance scores. Similarly, the average pretest and posttest scores control the internal validity threats: When people exhibit extreme scores on an initial test, one of the reasons for the extreme score may random error. On a subsequent test, that random component of the score is no longer so prominent and the person's score regresses, that is, moves back toward the average of the group. (Beins & McCarthy, 2012, p. 139) Therefore, the analyses and discussion of the results relied on the average performance scores of the two oral pretests, as well as the two oral post-test scores and the median to determine the effects of the treatments on the trainees' performance of speaking micro-skills using inferential analyses:

Oral Pre-T1 + Oral Pre-T2/2 = Oral Pre-test Aver. and Oral Post-T1 + Oral Post-T2/2 = Oral Post-test Aver.
To achieve all these, the test employed a rubric attached as appendix A to assess speaking performance adapted from http://www.teachingforexcellence.com/wp-content/uploads/2012/07/ WORLD-LANGUAGE-SAMPLE-WRITING-SPEAKING-RUBRICS.pdf. The twice administration of oral pretests before intervention enabled us to check the reliability of the test. The rubric consisted of four areas of performance assessment or speaking subskills commonly known as micro-skills. It was used to test their oral performance level in the prespecified micro-skills based on a 4-point Likert scale of 4.0 to 1.0. Therefore, the rating scales convey the following meanings:

Validity and reliability of the materials and tools
The training material or aural oral skills learner module was thoroughly revised in line with the comments given by three professors. Of these scholars, two were assistant professors in TEFL at Arba Minch University in the department of English Language and Literature and a senior professor at Hawassa University from the same department. Their comments were valuable for the making of a sound learner material that embedded mobile-based approach to teach aural oral skill lessons.
In addition, comments from teacher educators who were recruited for implementing the interventions in the research setting were found to be very helpful in rating each of the lessons in the three units of in the learner's material to estimate its reliability. Thus, they were allowed to rate each of the topics with the accompanying audiovisual texts and pre and post-aural oral activities as well as activities for a while listening sessions. They were informed to distinguish the suitable listening lessons from those having perceived feasibility problem in the lesson delivery and posing challenges during mobile-based lessons' implementation. They rated saying "yes" for suitable audiovisual texts and "no" for those not suitable.
To judge difficulty level of the aural oral skill lessons in the learner material produced by the researchers, implementer teachers used a rating scale from simple (1), fairly difficult (2) difficult (3) to a very difficult lesson topic in the checklist. However, the topics that were found to be said difficult (3) and/or very difficult (4) in the raters first assessments were also rerated if they were inappropriate topics, relatively ambiguous topics, very ambiguous topics or difficult topics in section two of the same checklist. Accordingly, they were asked to put if their remarks were to whether to revise/modify/simplify the lesson or totally to reject it.
From the implementer teachers' assessments, two lesson topics (lesson topic 2 and lesson topic 24) were found inappropriate to the participants' level and were seen as ambiguous. The following activities were also found to be difficult for the trainees to fully engage themselves in the prelistening, while listening and post listening sessions. Therefore, discarding these two lessons was suggestion given by the principal implementer and co-implementer instructors. However, they agreed the remaining 22 lessons were adequately developed for the training and were up to the level and coinciding with the training/lesson/objectives. Finally, to predict the material's suitability based on the implementer teachers' ratings, the alpha was estimated .87 and was above the accepted level of reliability coefficient.
The questions to assess the trainees' oral performances were adapted from A Guide to Assess Speaking Performance "Speak Practice Test: General Directions." Consequently, the reliability coefficient to determine the relationship between the oral tests was calculated using Pearson's correlation analysis technique based on the results of pilot interventions in that the correlation coefficient of the tests was .984 that indicated there was an excellent relationship and reproducibility capacity of the tool to yield the same results in other successive administrations of it to measure oral performance.

Procedure of the experiment
The physical setting typical to the classroom where the experimental intervention was carried out was chosen based on its WIFI accessibility, connection strength, and availability of flexible seats. Moodle (3.0), a mobile application software installation by the student was also reinforced at the onset of the training; therefore, they started to attend the lessons 2 days per week means 3-hour lessons a day impeccably augmented the trainees' weekly practice hours to six. To put this in effect, first, the participants were given usernames and passwords and advised to use the salient features of their mobile phones to further listening practices inside and outside the classroom context. Guided by the assigned teacher educators, trainees were also encouraged to download interesting audiovisual texts for listening materials that could help them increase their aural comprehension performance and serve them as inputs for oral and reflective practices. With mobile features such as Bluetooth, camera, voice recorder, e-dictionary, and internet, we are used to undertaking listening-based oral activities. Reflective oral exercise was one of the dominant methods to work on researcher-designed mobile-based lessons, assessing the trainees, signs of oral skill progress, completion of comprehension practices, and activities.
When the participants were outside classrooms, advised using Wi-Fi in the college compound or elsewhere to carry tasks on related topics and come back with them to have oral practices in the classrooms was found the prudent strategies that also made the learning ubiquitous. During faceto-face learning hours, when specially listening-based oral activities focused on engaging in the classrooms, the researcher's presence and attendance taking to check their presence in class and completion of learning activities of the day was crucial and thus were done strictly. Trainee teachers should attend listening for comprehension lessons and should do oral activities to develop their speaking skills regularly. Therefore, trainees used to get feedback from peers and their trainers on each of the specific oral activities they did in the classroom.
To make the learning a more student-focused one, the CLT approach in which mobile technology was to embed it in the instructional training implementation for the wholeness of the intervention s. Therefore, lockstep (individual), pairs, and small or large group work were the methods frequently employed as necessary in the classroom and after they completed listening to YouTube on links suggested for trainee activities outside the classroom. The post-listening sessions were to engage trainees in oral discussion activities to check their comprehension of the texts they listened to and promote the use of active learning methods, demonstrate critical and creative thinking, evaluate information and give critics, identify relationships, make logical associations, reflect on the listening session and so on. Accordingly, the trainees used to negotiate meanings and present information in the classroom orally. They did home take assignments at their disposal being independent and compared their work being in pairs and small groups in the classrooms and sometimes chatting online. Finally, they used to report to their teacher(s) and the whole class. Listening contents or subject matter were listened to provide comprehensible inputs (i + 1) for the oral activities followed by post-listening monologues, dialogues, oral presentations, and peer or group discussions during the intervention period. In addition, Harry (2015) said oral activities could involve many kinds of games such as role playing or social interaction simulating real-world interactions by using their own mobile devices.

Method of data analysis
To check the consistency between the teacher trainees' oral performance scores assigned by two different raters, predict the existing closeness of performances in the first test occasion (T1) and the second test occasion (T2) and confirm the reliability of the measurement tool (rubric for assessing oral/speaking performance). The scores of the two pre-tests were first analyzed using Pearson's product-moment correlations, and the two post-test scores were also analyzed for the same reasons. In other words, correlations between Oral Pre-test one (OPreT1) and Oral Pre-test two (OPreT2) were estimated to decide whether there were differences between the results and to predict interrater consistency of the tests administered before and after the interventions. Then, descriptive analysis techniques were employed to reveal the trainees' initial and final oral performances in figures and percentages in terms of their performance in each of the speaking/oral subconstruct skills: fluency, language control, content, and risk-taking. Khaizal et al. (2021) classified and treated the sub-themes of speaking skill as pronunciation, fluency, discourse, and spontaneously speaking that underneath language control, content (usage), and risk-taking subskills.
In addition, a regression curve estimate analysis was used to graphically display the extent oral performance scores were regressed and compare the effect of the treatments. It ensured administering both the pre-tests and post-tests twice before and twice after the interventions were appropriate and enabled to increase the accuracy of the general oral performance measures and rely on a group average score before and after the interventions. Thus, Wilcoxson's Signed Rank Test was used to reveal the overall oral performance change in the trainees and estimate the size of the effect of the treatments. However, Kruskal-Wallis's H test was run to understand the differences in the effects of the mobile-based instructional treatments across the four types of speaking subskills. Similarly, Kruskal-Wallis's default descriptive analysis meant to obtain medians of the pre-test and post-test average scores of performances before and after the interventions enabled comparing the effects and understanding of the changes in performance in each of the speaking subskills.
Generally, using the correlational analysis method, performances in Oral Pre-test 1 and Oral Pretest 2 were first compared to see if there were internal consistencies and relationships between the scores in the pre-tests and post-tests. Thus, the results from Oral Pre-tests and Oral Post-tests were correlated, described, and inferentially analyzed using Kruskal-Wallis's H and Wilcoxson's Signed Rank Tests to estimate the significance of the specific and general effect of the treatments on the teacher trainees' oral performance.

Results
The data that reveal teacher trainees' initial and final oral performances before and after the intervention are used to show test results descriptively in figures and percentages and to identify the level of the effects of the treatments on the specific skill performances, and inferentially reveal differences across the oral subskills and on the overall/general oral performance as a whole in this section as follows:

Correlational analysis
Pearson's product-moment correlation was executed to find the relationships between tests. Accordingly, two pre-intervention oral performance evaluation results showed a strong relationship between the oral pre-tests when the scores were assigned by rater one during OPreT1 and rater two during OPreT2 at two different time points before the intervention compared to each other. See, Table 1 for the correlations between the two pretests and the two posttests.
As seen from Table 1 above, the coefficient of correlation between the oral pretests was r = .75, pointing to a good correlation between the pre-tests, p = 0.000. The same method was also excited to observe correlations between the two post-tests after the intervention. The post-intervention correlation was r = .839, p = 000. It revealed that there also existed a good relationship between the two post-tests administered on two different occasions after the interventions. These results imply that there are interrater consistencies and good correlations between the tests for a correlation coefficient above .70 that is beyond the accepted level of a reliability coefficient for a good test to consistently produce similar results.

Effects of fluency, language control, content and risk-taking: A descriptive analysis
(1) Ho: There is no significant effect of mobile-based aural oral skill lessons on teacher trainees' performance in the oral subskills after receiving mobile-based aural oral skill lessons.
In order to evaluate the pre-and post-intervention oral proficiency of teacher trainees, two successive oral Pre-tests (OPreT1 & OPreT2) and two post-tests (OPostT1 & OPostT2) were administered before and after the interventions. Therefore, the results obtained in each of the subskills were analyzed and discussed on a descriptive basis in words, figures, and percentages supported by graphs and tables accompanying the analysis. Therefore, the effects of mobile-based aural-oral skills' instructional treatments on the teacher trainees' performance of oral fluency, language control (language flow), content (vocabulary and structure usage), and risk-taking (ability to be a creative user) subskills were descriptively narrated and identified in the following session successively. Similarly, the figures accompanying the descriptive analyses displayed the relationships between the number of participants and performance level in the lines. The spots above the lines also revealed extreme scores in the first pre-and post-tests as a result of the scores in the second pre-and post-tests regressing to the average of the group scores that enabled the prediction of the effects of the mobile-based aural-oral skill lessons on the trainees' performances in the oral subskills with curves that lied between them.

Fluency
As seen in Table 2, the descriptive analysis revealed that the trainees' fluency in speaking in the English language had a higher positive effect on the teacher trainees' oral fluency, which was between 56% and 60% in the post-test, but it was nil in the pre-test.
Assessment results revealed that, before the intervention, 13 (52%) and 12 (48%) of the participants in the study who took OPre-test1 and OPre-test1 had shown frequent hesitations that were reflected in frequent pronunciation difficulties while speaking in the English language. Their number declined to 7(28%) in both OPost-test1 and OPost-test2. This result was also identifiable from the number of trainees who improved their oral performance, which exceeded 14 (56%) and 15 (60%) in the OPost-T1 and OPost-T2 performances, respectively. This change was also noticed in their speaking with some hesitation and revealed their limited pronunciation difficulties. Similarly, the number of trainees who performed full hesitations due to the difficulties in pronouncing correctly in the whole parts of their speeches reduced to 4 (16%) and 3 (12%) in the OPost-T1 and OPost-T2, which initially accounted for 12 (48%) and 13 (52%) in OPre-test1 and OPre-test2, respectively.
Generally, due to mobile-based experimental interventions, more than half (14 (56%) and 15 (60%)) of the total participants in the study improved their fluency in speaking in the English language even though their speech displayed some hesitation and difficulty of pronunciation which accounted to be 0% of participants demonstrated hesitation and speaking difficulty before the experimental intervention. In the meantime, as mentioned above, the number of trainees who had shown frequent hesitations and serious pronunciation difficulties highly decreased after the   intervention training. Figure 2 displays fluency performance scores in the first tests, OPre-test1, and OPost-test1, regressed in the second tests, OPre-test 2 and OPre-test2 The graphs in Figure 4 display in the line that there were no extreme scores observed in the oral fluency pre-tests as the curve was missing entirely. Similarly, it reflected a perfect correlation of the scores assigned by the two raters, revealing a high interrater consistency. However, there was a negative relationship in that the number of participants sharply decreased as the level of performance increased. In contrast, fluency post-intervention scores graphically revealed the number of participants scoring high results in post-test and the level of their performance had a relationship closer to zero by which the horizontal line in the second graph displayed the positive effect of the mobile-based aural-oral skill lessons on the oral fluency of the trainee teachers. The descriptive analysis results above also tended to confirm this as the trainees' oral fluency performances significantly improved from speaking with full hesitations in the whole part of their speech to having few hesitations in the whole parts of their speech being a high positive effect as the performance rates to speak with hesitations decreased from 12 (48%) in the OPreT1 and 13 (52%) in OPreT2 to 4 (16%) in the OPostT1 and 3 (12%) in the OPostT2. The regression curve, in the second graph in Figure 3 and 4, also revealed the average performance scores of the group in the oral fluency post-test accounted 28% and 58% of the trainees and performed level 2 (having frequent hesitations during speech) and level 3 (having some hesitations during speech), respectively. It meant that 7 participants had frequently observed difficulty in pronunciation, but 14.5 (58%) individuals revealed only some pronunciation difficulties in their speeches. Generally, the curve revealed that the majority of participants improved their oral fluency proficiency at the level they could speak English with some hesitations and pronunciation difficulties, which was 0% before the interventions. (See, Figure 4)

Language control
Similarly, the study assessed the effect of the MALL approach on teacher trainees' language control in terms of flow and the extent of errors committed while speaking in the English language (accuracy) in figures and their percentages. As shown in Table 3, the pre-intervention oral performance assessments (OPre-test1 and OPre-test2) revealed that 2 (8%) and 0 (0%) of participants in the study mildly communicated in a manner that was easy communicating in the English language with few errors. However, after the intervention, OPost-test1 and OPost-test2 results revealed that

Rating Scales
Rating their number increased to 14 and was estimated to be 56% of the participants in the study in both cases. (See also, Table 3) It was a positive change brought by the mobile-assisted intervention training. The data in Table 3 show that 17 (68%0 of the participants in the two pre-tests (OPre-test1 and OPre-test2) displayed oral performances that were difficult to follow, but, after the intervention, their number was decreased to 8 (32%) and 9 (36%) as seen from the results of subsequent two post-test scores. In addition to this, the positive effect of the intervention could also be observed from the data that participants whose English was impossible to follow and had significant errors impeding their oral communication accounted for 6 (24%) in the OPre-test1 and 8 (32%) in OPre-test2. However, their number was reduced to 3 (12%) in OPost-test1 and 2 (8%) in post-test 2. As a whole, like its effect on the trainees' oral fluency, the intervention training positively affected their oral performance of language control during communication in the English language. Figure 3 compares performance changes in language control before and after the intervention and displays how the language control performance scores in the first tests, OPre-test1, and OPost-test1, regressed in the second tests, OPre-test 2 and OPre-test2.
As can be inferred from graphic lines and curves displaying relationships between the number of trainees and their levels of performance in language control in Figure 5, estimations of the extreme scores in the first tests as they regressed to the middle of the group in the second tests by pointing around the average score of the pre-and post-intervention test results, differences in performances of language control pre-tests before the treatments depicted the relationship being negative that the number of participants increased as the level of their performance decreased. However, some differences were observed between the scores independently rated by the two evaluators, and it revealed a low interrater inconsistency; In addition, the regression estimation above the line of negative linearity of correlation curved and denoted that a large number of the participants (17% or 68%) performed oral English which was difficult to follow and had considerable errors that impeded their verbal communications. In contrast, the language control post-tests graph revealed the number of participants scoring high results, and the level of their performance had a relationship closer to zero. And it had a less than moderate regression effect on the second post-test in the scores in the first post-intervention language control test. Average scores were dependent on analysis as a result. The postintervention results (as shown in the second graph below) displayed a moderate effect of mobilebased aural-oral skill lessons on the trainee teachers' performance of language control which was an increase from level 2 performance to level 3 performance as well (see in the appendage) because their figure increased to 14 or take 56% of the total participants in the first and second oral post-tests in each cases having a Level 3 language control skill that marked a high positive effect of the treatments on them. (Compare the graphs in Figure 5)

Content/use of vocabulary and structures/
Below is a descriptive matrix revealing the change in trainees' oral performance in terms of the trainees' use of language contents or vocabulary and structure in a detailed manner based on Table 4.
When the effect of the intervention training on the teacher trainees' oral performances was evaluated in terms of language content (use of vocabulary and structure), as can be inferred from the results in Table 4 above, those who used adequate vocabulary and correct structures and their oral performance exceeded the minimum requirement were 0 (0%) before and after the intervention. Similarly, trainees who met the minimum requirement were 6 (24%) and 3 (12%) in the OPre-test1 and OPre-test2, respectively. Here, it seemed there was a difference between the results of the two pretests but did not affect or alter the overall effect of the treatments on this particular oral subconstruct skill performance or content. However, this recharged to 13% or 52%, and 11% or 44% of the participants in OPost-test1 and OPost-test2 demonstrated using the necessary vocabulary and structure to meet the minimum requirements. These results confirmed that the effect was so high at this point. However, the rate of the changes could be said to be less but were not negative. Because 5(20%) and 3(12%) in OPre-test1 and OPre-test2, respectively, lacked the words and structures needed to fulfill the minimum requirements for oral communication. Therefore, the rate of under-minimum requirement performers decreased after the intervention even if there were still few trainees upon whom the training did not bring meaningful effect found to be 3(12%) in the OPost-test1 and 2 (8%) in OPost-test2 lacking in needed words and structures and preforming under minimum requirements. However, the intervention training had made significant effects on the trainees' use of vocabulary and structure while speaking in English. Figure 4 compares performance changes in the usage of vocabulary and structure (language content) before and after the interventions and displays how the scores in the first tests, OPre-test1, and OPost-test1 regressed in the second tests OPre-test 2, and OPost-test2.
As can also be inferred from graphic curves and lines of linearities displayed in Figure 6., estimations of the extreme scores in the first pre-and post-tests regressed to the middle of the group in the second pre-and post-tests by pointing to the curves that graphically bent around the average scores of the two tests both before and after the interventions. Extreme scores in   performances in the use of vocabulary and structures (content) in pre-tests before the treatments observed from the first graph in Figure 6 revealed interrater inconsistencies even though their performance was higher when compared with the pre-test performances in the preceding two oral subskills in that the number of participants sharply dropped as the level of performance increased. Therefore, extreme scores were made to regress to the middle and suggested average scores in OPreT1 and OPreT2 administered before the interventions. In contrast, the extreme score in the first post-test, concerning the usage of vocabulary and structures after the interventions, did not show a greater distance or disparities from scores in the second post-tests and confirmed the relatively a higher interrater consistency (see graph 2 in Figure 6). In other words, the interrater differences were found to be a minimum. Again, it displayed a higher effect of the mobile-based aural-oral skill lessons in the use of vocabulary and structures. The descriptive analysis results also confirmed the trainees showed significant changes in speaking English to a level less than easy to follow (performance level 3). The significantly positive changes implied that after one-semester mobile-based interventions, the trainees were being observed using the necessary vocabulary and structure of English to meet the minimum requirements to speak in the English language. The data revealed that as there were high increases in the number of participants to demonstrate level 3 performance after the interventions, there was a significant rise in performers from 6 (24%) participants in OPreT1 and 3 (12%) participants in OPreT2 to 13 (52%) participants in OPostT1 and 11 (44%) participants in OPostT2. (See and compare data in Table 4 with Figure 6)

Risk-taking
As also seen in Table 5, the results study revealed that no participants were found to use a very creative language, i.e., 0 (0%) demonstrated a usage of accurate words to clarify or convey meaning in the English language. There were 8 (32%) and 7 (28%) teacher trainees who demonstrated creativity and use of suitable words to clarify or convey meaning in OPre-test1 and OPre-test2. This number exceeded 17 (68%) in both OPost-test1 and OPost-test2, denoting that there were positive changes. However, in the evaluation to be moderately creative to use a few suitable words to clarify or convey meaning, the number declined to 5(20%) and 7(28%) in OPost-test1 and OPost-test2 when compared with the results performed in OPre-test1 and OPre-test2 that was 14 (56%) and 16 (64), respectively. This also witnessed the existing significance of the change in the trainees' oral performance in the English language. Those who orally performed not creatively in the OPre-test1 and OPre-test2 were 3 (12%) and 2 (8%), respectively.
The number of noncreative oral performers remained almost unchanged. Their number was estimated to be 3 (12%) and 1 (4%) in OPost-test1 and OPost-test2, respectively. However, the   effect of the intervention was positively significant. Figure 5 similarly compares performance changes in the teacher trainees' risk-taking ability before the intervention and after the intervention and displays how the performance scores in the first tests, OPre-test1, and OPost-test1, regressed in the second tests, OPre-test 2 and OPre-test2.
Figure 7 displays in the graphs the linearity of the relationships between scores for risk-taking, while speaking English was negative in the case of the pre-tests and closer to zero in the case of the post-tests which meant that there were scorer differences. The extreme scores were also highly regressed in the second oral pre-test, but the regression became low as a result of performance scores in the second post-test. So, relying on average test performance scores was believed necessary once again. The significance of performance changes in the ability to take risks positively as the curves denoted that majority of teacher trainees demonstrated the use of few suitable words to clarify or convey meaning by being moderately creative. However, after the experimental interventions, their risk-taking skills were promoted to a creative user level, which meant their speaking performance increased to be at the level of using suitable accurate words to clarify or convey meaning. The descriptive data in Table 5 also supported as there were positive changes in the rates of performers taking risks by using suitable accurate words to clarify or convey meaning in the English language increased from 8 (32%) in OPreT1 and 7 (28%) in OPreT2 to 17 (68%) in OPostT1 and 17 (68%) in OPostT2 (see Table 5). Similarly, the line went down to a level of performance increase in the risk-taking pre-tests before the interventions, but the line got to rise when the level of risk-taking performance increased after the intervention (see and compare data in Table 5 with Figure 7). In general, the null hypothesis was first rejected.

Effects on speaking subskills: inferential analysis
(1) Ho: The difference in the effects of mobile-based aural oral skill lessons on teacher trainees' oral performance across the subskills is not significant after receiving mobilebased aural oral skill lessons.
In order to compare the effect of the interventions with mobile-based aural-oral lessons on teacher, trainees' oral performance was administered twice before the intervention as pre-tests and twice after the intervention as post-tests. Descriptive statistics supplied by a default Kruskal-Wallis H Test was used to compare the significance of the effect of the treatment on the performances in the oral subskill before and after the interventions. When compared, the data in Tables 6 and 7 revealed the significant effects of the treatments on trainees' oral performance in each of the four speaking subskills. The result denoted the median of the oral fluency av. Post-test scores after experimental intervention were insignificantly (Md = 7.000, n = 25) when compared with the median of the pre-test scores (Md = 7.500, n = 25). However, the post-test scores in the language control, content, and risk-taking subskill performances after the intervention were significantly positive (Md = 8.500), (Md = 11.00), and (9.500), respectively, when compared with the medians of the pre-test scores in the language control, content and risk-taking sub-skills (Md = 7.000), (Md = 4.500) and (Md = 7.500), respectively. And the null hypothesis is rejected consequently. In other words, as also described in the descriptive analyses in the preceding sub-sections, the interventions had equal significant or positive effects across the different oral sub-skills.
To evaluate the differences across the four types of speaking oral subskills for the effects of mobile-based aural-oral skill lessons on the teacher trainees' oral performance, Kruskal-Wallis test helped identify the relationships and revealed insignificant differences, .368, p = .000 on the effects of mobile-based aural-oral lessons for four types of subskills (fluency, language control, content, and risk-taking, n = 25), and the null hypothesis was accepted.  (1) Ho: There is no significant effect of mobile-based aural oral skill lessons on teacher trainees' general oral performance after the trainees' participations in the mobilebased aural oral skill lessons.
Lastly, Wilcoxon Signed Rank Test was employed to analyze data that provided information on the compared change between oral performance scores before and after mobile-based interventions. It provided descriptive and inferential data analysis outputs based on which to accept or reject the null hypothesis.
As shown in Table 8. he results denoted that the median of the oral performance post-test aver scores after experimental instructional interventions with the mobile-based approach was significantly higher (Md = 9.5000, n = 25) when compared with the median of the oral performance pretest aver scores (Md = 7.7500, n = 25).
Confirming a result in the above paragraph, Wilcoxson's inferential analysis result-based computing mean ranks of the pre-test and post-test evaluated the changes in the trainees' overall oral performance as a result of the interventions with a mobile-based approach were statistically significant or not. Wilcoxon's Signed Rank Test revealed a statistically significant change in the teacher trainees' oral performance following participation in the intervention training, z = −4.541, p = .000, r = 0.617. "r" signifies effect size that was 0.67, and implied that there was a high effect of the independent variable (mobile-based aural-oral skill lessons) over the dependent variable (oral performance). Therefore, the third null hypothesis was not accepted.

Discussion
As it can be glimpsed from the analyses' results in the preceding section, the effects of mobile based aural oral skill lessons on teacher trainees' performance in each of the oral subskills and on their general oral performance were presented as follows: Concerning the significance of the effect of mobile-based lessons on the teacher trainees' performance of oral fluency after they participated in the mobile-based aural oral skill instructional intervention training, the training brought significant positive changes in the trainees' oral fluency in the English language. This was identified from the trainees' level of fluency performance which significantly improved after receiving the mobile-based instructional treatments, so their speaking in the English language revealed some hesitation and fluency difficulties to pronounce words and expressions in the language that was rated to be fluency performance level 3 which was initially estimated to be fluency performance level 1 and level 2. The number of trainees demonstrated fluency level 3 in the OPost-T1 and OPost-T2 accounted for 14 (56%) and 15 (60%) from the 0 (0%) initial performance both to speaking English having a smooth language flow and good pronunciation and to speaking with some hesitation and pronunciation difficulty. This result conceded to Ahmed et al. (2022) that identified Duolingo and WhatsApp mobile applications had the same positive effects on the speaking fluency of the Iranian EFL learners. Hammam (2020) also identified mobile-based learning as having the same positive effect on EFL students' oral performance.
However, the significance of the effect of mobile-based lessons on the teacher trainees' performance in language control after receiving mobile-based aural oral skill instructional treatments, the trainees brought significant positive changes in their language control performance while speaking in the English language. There was also a negative relationship between the number of participants and their performance level in language control before the intervention. However, the language control performance progressed being closer to level 3 performance after the intervention. The descriptive results showed that the trainees' language control ability improved and largely tended after the interventions to meet the minimum requirements to speak smoothly in the English language. Initially, before the interventions, the number of participants speaking English in a manner that was a bit easy to follow and communicate massage with few errors constituted 1% or 4% of the participants. However, after the interventions, their number exceeded 14% or 56% of the teacher trainees who participated in the intervention training. Corroborating with the current finding, Ahmed et al. (2022) identified that Duolingo and WhatsApp mobile applications had significant positive effect on the EFL learners' speaking accuracy.
Concomitant to the preceding two findings (the effect on fluency and language control subskills), the significance of mobile-based aural oral skill lessons on the teacher trainees' performance in the usage of language content or speaking the English language using necessary vocabulary and structures (lexemes/words and grammar) at the level that meet minimum requirements to be considered a good speaker of the language (performance level 3) were counted to be 6(24%) and 3(12%) in the OPre-test1 and OPre-test2, respectively. Parallel to this finding, Khan et al. (2018) noted that the lack of vocabulary is one of the main factors in students' inability to speak English. However, these figures increased after the intervention to 13 (52%) and 11 (44%) in the OPost-test1 and OPost-test2, respectively. And Khan et al. (2018) proposed the use of MALL as a lesson approach to increase vocabulary to the development of speaking proficiency of Saudi EFL learners. La'biran (2021) explained blended learning is generally an effective strategy to improve students' vocabulary acquisition. Likewise, in the mobile embedded EFL learning, Beyranvand and Rahmatollahi (2021) empirically identified that the students in the Instagram (experimental) group outperformed the control group students in the mastery of new vocabularies. Similarly, Baleghizadeh and Oladrostm (n.d.) concluded that the knowledge of English grammar boosts in the mobile phone use. A meta-analysis of empirical studies grounded social constructivist theoretical model to integrate MALL in teaching the English language confirmed the positive effect of a mobile-based learning on students' knowledge acquisition (Marzouki, et al., 2017). In general, if we frequently expose students to apply mobile apps in EFL learning, their aural and linguistic competences are susceptible to highly increase (Ramos & Valderruten, 2017). Therefore, the study also probed significance of mobilebased aural oral instructions that brought significant positive changes in the teacher trainees' performance to use English vocabularies and structures (language content) in their oral communication.
When the trainees' performances were assessed to determine the significance of the effect of mobile-based lessons on the teacher trainees' risk-taking skill while speaking in the English language after exposing them to mobile-based aural oral skill instructional treatments, their performance significantly increased to take risks and their performance changed accordingly to the level of being a creative user of suitable words to clarify meaning intended to be conveyed. As a result, the descriptive information revealed that 8 (32%) and 7 (28%) teacher trainees demonstrated a creativity to use suitable words to clarify and convey meaning as they spoke in the English language during the OPre-test1 and OPre-test2. These figures exceeded to 17(68%) in both OPost-test 1 and OPost-test 2, denoting that the risk-taking skill performance changes after the interventions were found positive. For example, Ebadijalal and Yousofi (2021) investigated that mobile assisted oral peer feedback positively affected students' risk-taking performance being measured as one of the speaking sub-constructs in the assessment of EFL learners' oral proficiency. In general, the results so far indicated that the use of mobile phones had positive outcomes in the development of trainees' oral fluency, language control skill, vocabulary and structure (content) mastery, and ability to take risks while speaking EFL. Therefore, the first null hypothesis was rejected based on the findings so far.
Accordingly, the significance of the differences in the effects across the oral subskills was not significant, .368, p = .000. In other words, the Kruskal Wallis' inferential analysis revealed the interventions with mobile-based aural oral skill lessons had a positively significant equal effect on them in their performance in the oral subskills; therefore, the changes did not have significant differences in the level of the effects on the performances across the oral subskills. Consequently, the second null hypothesis was rejected as well.
Concerning the third null hypothesis, the analysis results indicated that a mobile-based auraloral skill instructional treatment after the teacher trainees' participation in the mobile-based aural oral skill intervention training brought a significant positive change in the trainees' overall/general oral performance, z = −4.541, p = .000, r = 0.617, having a large effect size (r). Mobile applications assist and optimize students' speaking performance and critical thinking skills in English language learning (Kusmaryani et al., 2019). Tonekaboni (2019) also confirmed that students benefitted from learning English Daily (a mobile learning app) and displayed better performance changes in speaking the English language. Qooco (a mobile app/software) increased students' spoken and written achievements in the English language (Bitter & Meylani, 2016). In addition, mobile built-in features and learning applications could be the other possible tools to help learners enhance their speaking skills in MALL environments (Rajendran & Yunus, 2021). Therefore, the findings of the current study and the empirical studies referred to so far disfavored the third null hypothesis so that there is no significant effect of mobile-based aural-oral skill lessons on teacher trainees' general oral performance after the trainees' participation in the mobile-based aural-oral skill lessons was rejected at the end.
In general, the data analyses and discussion of the results revealed that there were significant effects of mobile-based lessons on the teacher trainees' performance in the oral subskills, having equal magnitude of the effects in the performance across the oral subskills, and on the overall oral skill performance after they received mobile-based aural oral skill lessons or training.

Conclusions and recommendations
Even though Artyushina and Sheypak (2018) said their students frequently use their mobile phones for entertainment: to listen to music, watch films, and play computer games, the mobile phones will help achieve tremendous outcomes in EFL learning. The current study also confirmed that embedding mobile technology in the EFL instructions boosts trainees/students' speaking fluency, control of language (ability to communicate orally with few errors), use of content (vocabulary and grammar), and risk-taking skills (being creative to use suitable words to clarify and convey meaning). The lack of a student's aural training highly affects his speaking skill development more than the lack of experience in the other language skills. Therefore, teaching listening skills as early as possible will provide the EFL learners with the necessary comprehensible input (i + 1) in the later practice of speaking in the target language. As was also identified in this study, mobile-based aural-oral skill lessons significantly affect the teacher trainees' performance developments in the speaking micro-skills and the overall/general oral performance if the EFL learners and instructions entertain integration of the approach to deliver aural-oral skill lessons. Therefore, the researchers recommend EFL teachers at various levels be astute and creative enough to integrate mobile phone and social media outlets into the EFL instruction. Similarly, we recommend focusing on applying the salient mobile features, mobile learning platforms (along with Moodle 3.0 mobile app), and institutional internet access to create lessons by customizing social media-based content (EFL texts) to provide learners with authentic listening materials and to undergo oral reflective practices in classrooms and beyond. Moreover, teachers and teacher educators in higher institutions should conduct further studies on how a mobile phone can reduce trainees' frustrations with speaking English and minimize a vividly perceived pronunciation problem students are encountering because of heavy first language influences. They should also study how mobile phones as an emerging learning technology can address the EFL learners recover from proficiency downing linguistic or pronunciation fossilization due to a high level of interference in their mother tongues. By the same tokens, EFL teachers and researchers in the field are advised to undertake a study of how experimental interventions with mobile-based lessons affect the trainees'/students' learning styles as learning style change is something observed in the learner's language studying habits in the long run as a consequence of the experimental interventions.