EFL learners dropping out of blended language learning classes: A replication of Stracke (2007)

Abstract Studies with an explicit focus on dropouts in blended language learning (BLL) are rare and non-existent in the Asian context. This study replicates the early qualitative interview study by Stracke (2007), who explored why foreign language learners drop out of a BLL class. While the 2007 study was carried out in the German higher education context, we conducted this study at a university in Vietnam, where we conducted semi-structured interviews with five students who had left their blended English course after the first semester of study. Our findings indicate that the successful complementarity and integration of the blend components, the crucial role of teacher support and feedback within a learner-centred environment, interactive learning materials, a high level of interaction, and a good relationship between students and teachers are key for students’ perception of a successful blended class and retention. The lack of complementarity between the components of the blend remains a major reason for students’ dissatisfaction that resulted in them leaving the course in both the 2007 study and this study. Our study allows for a deep understanding of the reasons why Vietnamese EFL students leave a BLL course, thus providing some evidence for pedagogical adjustments for the delivery of current BLL classes in Vietnam and similar contexts. Understanding the reasons why students drop out can help improve the effectiveness of these programs and lead to higher retention rates, a reduction of costs (both financial but also emotional), an increase in student satisfaction, and a better student experience.

Dropout in language education has drawn the attention of researchers from different perspectives (e.g. Lee & Choi, 2011;Modarresi & Javan, 2018;Wentao, Jinyu & Zhonggen, 2016) and is also one of the issues found in BLL programs (Friðriksdóttir, 2021a(Friðriksdóttir, , 2021bStracke, 2007). Understanding the reasons why students drop out can help improve the effectiveness of these programs and lead to higher retention rates, a reduction of costs (both financial but also emotional), an increase in student satisfaction, and a better student experience.
This qualitative replication study aims to investigate why EFL students drop out of a BLL program in a higher education institution in Vietnam through a replication of Stracke's (2007) study, in which she explored why foreign language learners (French, Spanish) drop out of a BLL class in the German higher education context. By repeating the earlier study's design and a subsequent interpretive comparison, this study has generated a richer and deepened understanding of the dropout phenomenon, then and now. The comparison of the reasons for leaving the course has revealed interesting commonalities and differences and has implications for future developments in BLL. Stracke (2007) pioneered a qualitative study about dropout in BLL in the late 1990s. Replicating this early study allows for a deeper understanding of why students dislike their BLL experience to such an extent that they leave the course. In her study with three course leavers, Stracke used semistructured interviews to investigate the reasons behind these students' decision to leave a BLL course in a German higher education context. The main causes of student dropout were lack of support, poor complementarity between the face-to-face and computer-assisted language learning (CALL) components of the blend, lack of paper materials, and rejection of the computer as a medium of learning. Just like in the 2007 study, the focus of this study is on the language learner. "[ : : : N]ew technologies in language learning [have] come a long way, they are increasingly part of the mainstream in language learning and teaching" (Smith & Schulze, 2013: i), and it seems timely to reconsider the reasons why a BLL environment does not work for some learners. To understand the significance of dropout in BLL, a conceptual understanding of dropout in language learning in general, and online (language) learning in particular, is needed.

Dropouts in language learning in general
The phenomenon of dropout in language learning at the tertiary level has received some attention (Evans & Tragant, 2020;Martín, Jansen & Beckmann, 2016;Modarresi & Javan, 2018;Rowsell, 1992), showing that there are several reasons for dropout in language learning at higher education. The two most recent studies investigated both external and internal demotivating factors that lead to student dropout.
The study by Modarresi and Javan (2018) was conducted in an EFL context in Iran. Participants in the research were 20 teachers of English and 90 students at private English institutes. Both questionnaires and semi-structured interviews were used for data collection. From the teachers' perspective, the most frequently cited factors leading to dropout included students' inability to use English (11.3%), less effort (10.6%), interest (9.9%), teacher knowledge (9.3%), financial problems (9.3%), and higher age (7.9%). No information was provided about the age range. Specifically, internal factors (demotivation and emotions) and external factors (teacher, teaching methodology, administrative decisions, and evaluation) contributed to dropout. The students mentioned a lack of effort, self-confidence, and motivation, as well as an external factorthe imprecise evaluation of their current proficiency levelsas factors that made them leave the course. The study by Evans and Tragant (2020) investigated the reasons behind adult EFL learner dropout in a language school of a public university in Barcelona, Spain, using a questionnaire with both qualitative and quantitative components. They found that dropout students tended to retain negative views of their teacher and the course, blaming their dropout on poor teaching practice, a lack of speaking practice, and a discrepancy between their desired level and their perceived stagnant level.
2.2 Dropouts in online learning (including online language learning) Dropout in the online learning environment has received considerable attention. Lee and Choi's (2011) review provides a useful overview of 35 studies investigating online course dropouts in tertiary education from 1999 to 2009. The study identified 69 factors that influenced students' decisions to drop out and classified them into three main categories: (1) student factors (academic background, demographic characteristics, relevant experiences, skills, psychological attributes), (2) course/program/institutional factors (assessment, course design, delivery mode, institutional factors, interaction), and (3) environmental factors (work/time commitment, supportive environment). The researchers then examined the suggested strategies to overcome dropouts. They found that although online course dropout factors largely resulted from student factors, the suggested strategies to reduce dropout rates were focused on course/program factors. There was also a limited number of strategies in addressing student or environmental factors, or no strategies that addressed students' lack of relevant experiences regarding student factors or increased work commitment in relation to environmental factors. The study, therefore, recommended further studies to learn more about these dropout factors.
Based on the factors identified by Lee and Choi (2011), Lee, Choi and Kim (2013) continued to examine the differences between persistent and dropout students enrolled in an online course offered at the Korea National Open University. Quantitative data were collected via two online questionnaire surveys. The results showed academic locus of control (how much control a person feels they have in their behaviour) and metacognitive self-regulation for learning (the controlling of a thinking process or learning activity by the learner) were important factors influencing the dropout of students. Similarly, Rostaminezhad, Mozayani, Norozi and Iziy (2013) reviewed the findings of 24 major studies via a quantitative content analysis to identify the theories that explain the success rate of e-learners. This study indicates that e-learner dropouts are less self-regulated than persistent learners.
In the context of online language learning, Budiman's (2018) study conducted at an open university in Indonesia is of interest. In a qualitative longitudinal study, Budiman examined the reasons for dropping out of a distance English language learning program. This study indicated that the major reasons that led the students to drop out were the lack of basic skills in English, unmet expectations, feelings of isolation, and the inability to balance work, family, and study responsibilities.
These studies, conducted in many different contexts, show that the causes of learner dropout are diverse. They straddle learner-related, course-related, and learning environment-related factors. In the next section, we focus on studies that investigated dropout in BLL environments. Friðriksdóttir (2018Friðriksdóttir ( , 2021aFriðriksdóttir ( , 2021b conducted three recent studies, all part of a major project, with a focus on student dropout. In the first phase of the project, Friðriksdóttir (2018) examined the student nature of online behaviour and student retention. Friðriksdóttir tracked data collected over eight years on 43,000 users of open guided online courses in Icelandic as a second language. She also compared the different modes (open self-directed, distance, and blended) that the online courses were delivered in. By tracking students' actual participation throughout the courses, the results revealed that there were large dropout rates at the beginning of the courses, and the blended mode was more likely to retain students than other modes. The study also highlighted the key factors that influenced the online behaviours of non-completers, namely the organisation of the course content and assignment submission. However, there was no straightforward evidence for learning goals or types of learning objects that could influence the dropout.

Dropouts in BLL
In the second phase (IOL2), Friðriksdóttir (2021aFriðriksdóttir ( , 2021b specifically explored factors that might affect student retention by tracking 400 users over eight years. Friðriksdóttir (2021a) discovered some content-specific factors, such as curated and sequenced course structure, scaffolded presentation of input, and variety in types of learning objects, to be important for learner motivation and retention. Notably, some non-course-related factors, such as time constraints, inappropriate proficiency level, or lack of motivation, were also found to affect learner retention. Friðriksdóttir's (2021b) findings revealed that the students' initial goal to complete was a significant predictor of course completion, with most students of the blended mode having an intention of completion. In addition, the blended-and distance-mode students reported that tutor-specific factors, which included private interaction with the tutor, tutor support, detailed introduction to the organisation of the course, its goals, and technical functions, and set syllabus, were all motivating factors for their course completion. Friðriksdóttir's comparative studies indicate again the mix of student-related, teacher-related, course-related, and learning environment-related factors that influence student retention or dropout.
The current study replicates Stracke's (2007) research in an Asian EFL context. Dropouts in Vietnamese EFL programs in general and at the tertiary level have not yet been investigated. With this study, we seek answers to our research question: Why do EFL students drop out of a BLL program in a higher education institution in Vietnam?

Methodology and method
This qualitative research replicates Stracke's (2007) study of dropouts in a BLL context at a German university (L1 = German; L2 = French/Spanish) in the Vietnamese higher education context. Hence, the research participants' L1 (Vietnamese), the target language (English), and the software used have changed. Further, while the students in the 2007 study were non-language major students, the participants in the current study were all majors in English. However, we follow the same research approach (qualitative) and use the same method (semi-structured interviews) to investigate a group of students who dropped out of their blended English class, replicating specific aspects of the original qualitative study. Such studies are often described as approximate replication studies (Porte, 2013), particularly within the quantitative paradigm. Nonetheless, the approach also adequately describes this qualitative replication study.
Thus, this study responds to Smith and Schulze's (2013) call for qualitative replication studies, seeking to "obtain a clearer picture of phenomena observed" (Smith & Schulze, 2013: ii) and "generate 'a richer and deepened' understanding of the phenomena" (TalkadSukumar & Metoyer, 2019: 2). The specific phenomenon under investigation is the phenomenon of students dropping out of BLL classes. We used semi-structured interviews to gain insights into the participants' experiences in the blended English classes that they decided to quit. Just like in Stracke's (2007) study, our interview protocol comprised open questions that allowed the research participants to freely express their views on the blended English course they had attended. The focus of the interview was on the student's decision to leave the course and their reasons for this decision. We piloted the interview protocol with two students to ensure that we gave participants ample opportunity to share their thoughts. Although these dropouts constitute only a subgroup of all the students who attended the blended English course under investigation, the study of such "extreme" (or outlier) cases (Patton, 2015) is valuable as they assist in the exploration of a field of investigation from its margins.
The researchers' relationship with the organization where the study was conducted differed according to their home university. The Australia-based researcher did not have a formal affiliation with the university in Vietnam but had relevant teaching experience in Vietnam's university sector. The two Vietnam-based researchers work at the institution but do not teach at the Distance Education Centre where this study took placethat is, they did not have a pre-existing relationship with the research participants. Along the insider-outsider continuum (Aguinis & Solarino, 2019), the research team's relationship with the organization and the research participants can best be described as a middle position, allowing for a deep understanding of the students' experience in the Vietnamese context.

Research site and participants
The participants in this study are (pre)intermediate Bachelor of English Language (Cử nhân Ngôn ngữ Anh) students who started their studies in April 2021 in the Distance Education Centre at a university located in a capital city in Vietnam. The standard time for the whole bachelor is four years. For the first two years (four semesters), students mostly study the language skills of listening, speaking, reading, and writing. The time of study is often in the evening on weekdays and on weekends (either daytime or evening) because most students work and study at the same time. The information related to the delivery model of the course was provided in the course description.
In their first semester, students are required to study eight units that cover the four skills of listening, speaking, reading, and writing, as well as one unit in study skills. From previous cohorts, we knew that there was a dropout rate of 10%-20% in the first semester, with an intake number of approximately 150 students. The April 2021 intake consisted of 273 students, 40 (15%) of whom did not enrol in the second semester in December 2021. We invited these 40 students to participate in our research via the phone number they had provided. In the initial screening process via telephone calls, we excluded the students who reported dropout reasons that were completely unrelated to the quality of the instructional experience, such as moving away from the city where they attended university. Five students agreed to participate in our study. These students had not re-enrolled in any unit in the second semester of their coursethat is, they had dropped out of their Bachelor of English Language course during or at the end of the first semester. During the semi-structured interviews, they reflected on the reasons why they dropped out of the bachelor course. The demographic details of the five participants are provided in Table 1. The participants work in administration and business and are, with one exception (Tan), in their 30s or 40s.

The blended model -Technology and materials
The Bachelor of English Language course was delivered in a blended model, combining face-toface classroom, synchronous online learning, and self-study. The ratio of face-to-face and synchronous online learning differs depending on the nature of each unit in the course. For all language skills units, the ratio is typically 50/50. In the cohort under investigation, the students started in this typical constellation. However, due to COVID-19, after the first five weeks, the blended delivery mode changed into a 100% online mode because Vietnam experienced its second hard lockdown. This meant that the students met their teacher and other students for the remaining teaching time of the semester (approximately 15 weeks) only in the online environment. The switch to remote learning, although not surprising during the COVID-19 pandemic, created an unexpected challenge (Aguinis & Solarino, 2019) during the study, as it meant a reduction in face-to-face learning for this particular cohort. Both the face-to-face mode and the synchronous online mode require real-time interaction between teachers and students. The face-to-face learning took place in a classroom at the university, while teachers and students met in Teams or Zoom for the online teaching.
The textbook Pathways (Blass & Vargo, 2018;Chase, 2018) was used in all language skills units, both in the face-to-face and online synchronous classes. For self-study, students used MyELT (n.d.), which is the web-based learning management system (LMS) designed to support learning with the textbook through online workbook exercises, practice tests, and other additional activities that support student learning. For exchanging information and for communication between students, and students and teacher, students formed Zalo groups. Zalo is one of the most popular apps in Vietnam (Prodima, 2022).

Data collection, management, and analysis
Data were collected through face-to-face semi-structured interviews in the capital city where the university was located. The place of the interview was either a room at the university or a café, depending on what was convenient for interviewees. The interviews varied between 26 and 37 minutes in length and were audio-recorded. All interviews were conducted in Vietnamese. The two Vietnam-based members of the research team are bilingual in Vietnamese and English and had offered to conduct the interview in Vietnamese, which all interviewees preferred. We had also provided all information about the research project, including the participant information and consent forms, in English and Vietnamese to ensure that these (pre)intermediate learners of English fully understood what the project was about as well as their involvement. The two bilingual research team members transcribed the interviews verbatim in Vietnamese. Each transcript was labelled, indicating the interviewee's pseudonym and the date when the interview was conducted. Subsequently, they translated the interviews into English, performed reciprocal peer checking, and agreed on the final translations.
We conducted a thematic analysis to investigate the interview data (Braun & Clarke, 2006). First, we analysed all interviews individually, starting with the repeated reading of all transcripts, to ensure a good overall sense of the complete data set. Because we were interested in understanding the participants' views, no work was undertaken with any a priori categories when analysing the data. Subsequently, we constructed common influential themes across the five cases. All three researchers were involved in the analytical process through recurring peer checking the codes and themes identified in the process.

Findings
We analysed each case individually first, before we identified six common themes across the five cases. In this section, we present the main reasons why each of the five students dropped out of the blended English course. Subsequently, we present the six salient themes that we identified across the individual cases. The main reason why Lan dropped out of the course was that she felt stressed, unable to keep up with the pace of the class, and thus lost motivation to study. Lan describes her feelings with words like "stressful" (L/10), "lost", "overwhelmed", and "falling behind" (L/12). Lan rated her academic performance lower than that of other students and considered herself to be quite timid and lacked confidence in her academic ability. Lan was self-aware that she needed to be self-directed in her studies, so she tried to complete the assigned exercises by herself. However, when there was a problem that needed an explanation, Lan chose to remain silent and try to solve the problem herself. Lan faced difficulties in completing the tasks given: "the amount of homework is too much: exercises in face-to-face classes, on MyELT and the extra homework" (L/22) assigned by teachers. What is more, the teacher did not correct the exercises on the system, but only assigned the exercises for students to complete. This lack of feedback made it difficult for Lan to maintain her interest in completing the exercises. For example, in paragraph writing that requires a wide range of vocabulary, Lan said that she did not have enough vocabulary. Although Lan can use Google Translate, she did not think her writing skills could be improved because she did not know "how to write, how to choose the right words" (L/44). Thus, she often skipped the exercises. She felt that "I don't have anyone to help me, so I am behind and become more and more behind every day" (L/12). Lan gradually lost motivation and chose to give up.

Kim -Limited autonomy and choices for self-study; teachers need to be a good coach
For Kim, the reason for stopping the course was largely because the course had little opportunity to develop learner autonomy and provide choices and support for learners in the self-study phase. Kim commented that although "the self-study component (MyELT) helps students to actively study at any time at their convenience" (K/16), it did not meet his expectations. In his opinion, the self-study part "should be called supplementary exercise, but this program considers it a mandatory part for learners" (K/8). According to Kim, while studying with computer-based exercises, students must actively learn, self-check, and rewrite the correct sentences, with restricted teacher support for the self-study phase. The teacher role should focus on "assigning tasks and paying attention to student attendance on the computer system, following the percentage of online exercises completed", but not on "correcting paragraph errors or the exercises on the platform". Kim believes that the role of the teacher is important in supporting these self-study modules, acting as "a good coach in sports" (K/20).

Tan -Teaching is traditional and book-based and does not do justice to a learner-centred approach
The biggest obstacle for Tan is the traditional way of learning, which is not consistent with the nature of the course. The course focuses on learning new vocabulary and grammar sections in class, which he finds unnecessary for him. Tan said that with the internet, students can look up and study by themselves. Moreover, there are abundant exercises or supplementary materials online. For him, the learning content was "repetitive, and also boring" because "the content in the book and the homework exercises on the computer are almost the same" (T/16).
Tan claimed that, in "the 4.0 technology era" (T/20), teachers need to take advantage of the strengths of technology in teaching. The traditional way of learningthat is, teachers providing materials for students, students gathering in class, students listening and being called to give answerstakes time while making students passive. He believes that for writing, "learning to write online is more effective".
Students will have more time to look up, learn and write on their own, then submit their work online for the teacher to check. And teachers, instead of waiting for students to complete their writing in class, use that time to carefully check and correct each student's writing.
That way, both sides can save time and teachers can know the students' level so that the students can improve through time (T/20).
According to Tan, even while teaching online, teachers still teach in the traditional way, which means "too much dependence on the textbook". In fact, "there is a lot of teaching, explaining, and careful teaching about sentence structures". "Specifically, for speaking, based on specific topics, teachers give exercises, then prepare vocabulary, then divide students into groups. The organization seem [sic] dated and has not promoted the strengths of the students" (T/28).

Mai -Feeling sidelined and isolated and fails to catch up with learning
Mai dropped out because she felt sidelined and isolated in the class. She admitted to having a poor connection with the teachers and other students; hence, the communication between them was insufficient and inefficient. For example, when she was late for class or could not complete learning tasks, she did not get enough support or attention from the teacher. She expected her teachers to show more concern for her performance: "The teacher does not have any feedback if I do not come to class or come late. If they see that I don't do my homework, they think I'm lazy" (M/30). Her feeling of isolation also came from her classmates who did not communicate with her frequently: "In classes when I have to work in pairs or in groups, I notice that many of my friends don't seem to like working with me" (M/40).
Further, Mai admitted that she failed to "keep up with the intensity" (M/36) of her study. She explicitly complained about the number of tasks given: "There are many homework exercises and many online self-practice exercises" (M/36). As a result, Mai constantly faced the feeling of guilt for not completing the heavy workload assigned by the teachers. She was not comfortable with that feeling: "it's like I don't cooperate with the teachers, so I feel embarrassed too" (M/32). Gradually, Mai lost interest in learning and developed a feeling of isolation and redundancy. She explained her disappointment when not getting enough emotional support: "I feel my mood is gradually decreasing, I am not excited to go to class anymore" (M/40).

Viet -Expectations for a more flexible model with relevant learning contents
Viet discontinued his study mainly because he found the learning time not suitable and not flexible enough. Viet's expectation when enrolling in the course was to participate in asynchronous online learning in which students can learn at their own pace and when they are free. He was disappointed when he had to "follow a fixed schedule", "study at fixed hours", and "go to campus to sit for exams", which he thought was "very inflexible" (V/32). He could describe what he wanted very clearly: "I like the type of study that allows us to self-study when we have free time, but I don't like to be confined to the specific hours and content of each day" (V/40).
In addition, Viet was disappointed with the learning content and learning activities. He believed that the learning content was not practical enough in comparison to his needs: "I found the contents of the course was not what I expected. I want them to be more practical" (V/42). He believed that even when he completed all the tasks and exercises, it would not help much in improving his proficiency and meeting his needs. His need was "simply to be good at writing letters in English and reading documents and giving presentations" (V/48). As for the learning activities, Viet believed that many of them were irrelevant to his needs or did not meet his desire: "Many classroom activities make me feel that there are contents that do not match my needs, and I like to learn according to my own abilities and needs" (V/48). Later, he provided some examples of irrelevant activities, such as "learning speaking by recording" (V/56), "finding stress", and "identifying incorrect pronunciation" (V/72).
In the following, we will present the six common themes identified across the five cases. We found four reasons for dropout that indicate what students miss: first, the lack of teacher support and feedback and, second, the lack of learner-centredness/autonomy. The lack of interactivity in online materials (third) and the lack of complementarity and integration of face-to-face and online components of the blend (fourth) refer to the course design, whereas the last two reasons, the importance of interaction (fifth) and relationship with peers and teachers (sixth), draw attention to the learning environment.

Themes 4.2.1 Lack of teacher support and feedback
Participants mentioned that the online homework section lacks teacher support, both in terms of academic and emotional support. For example, Kim commented, "teachers don't understand how students actually learn on their own, how they complete the exercises and how their language has improved through those exercises". Moreover, "once teachers do not grasp the reality of what students need, what is missing, what is wrong, they certainly cannot shape and correct", and "teachers can hardly follow the development of students' language to have reasonable adjustments to support students in the following lessons" (K/12). For online speaking, for example, he said, "I don't know what my weak points are that need to be improved, what my strengths are that need to be promoted" (K/14). Although Lan agreed that teacher support in face-to-face classes is good, for the self-study component, she would like "a coach so that I can ask for advice whenever I need" (L/38). Tan shared the same needs, claiming that "what I need is better teacher support for the self-study phase" (T/30).
For the self-study phase on the online platform, "teachers only check to see if students have completed the exercises or not but not correct student's homework". That is why Tan considers this type of learning to be "formal" but not effective because teachers do not know the actual level of students to give timely support (T/10). Likewise, Kim also believes that the software is considered an attendance requirement, based on the number of assignments completed, which is not reasonable (K/16).

Lack of learner-centredness/autonomy
Some of the participants felt that there was a lack of learner-centredness in the blended English class, in particular because of the heavy reliance on the textbook and the computer software. Tan, in particular, found that the course's reliance on prefabricated materials can stifle students' creativity and curiosity to find things out for themselves. He also found that the traditional teacher-centred teaching style during class time did not do justice to the blended learning environment. He wants the teacher to guide students in their learning: "so what teachers need is to suggest and guide students to actively learn on their own" (T/20). Kim echoed these views when he expected the teacher to be a "good coach in sports" (K/20).

Lack of interactivity in online materials
Participants reported that online exercises are not interactive. For example, Lan said that most speaking exercises are in the form of automatic speech tasks, focusing on pronunciation practice. Lan added, "I sometimes repeat the sentences or sometimes the machine gives me a topic. I must speak myself and record" (L/34). Similarly, Tan commented that "the speaking and writing parts are limited, the topic corresponds well to the content learned in class, which is good, but the speaking part is full of repetition, like pronunciation practice, no interaction" (T/24). The organization of "the student speaksthe machine asksthe student repeats the available answers, mainly for pronunciation practice" (K/10) results in "non-responsive act", or "autism" (L/28). Viet, similarly, expressed that he preferred an "online speaking software that can help learners interact with each other more", the one that "has the same features as talking with real people" (V/56). Furthermore, the online materials do not give feedback. For example, Lan said, "Many exercises on the online system only give answers without explaining why it is right, or why it is wrong" (L/16). Mai said she no longer "pay[s] attention to right and wrong anymore", because "right or wrong is just the answer", and she does not know "what should be done to make it right" (M/34). It seems as if the lack of feedback in the online materials aggravates the perceived lack of teacher feedback and support.
These quotations reflect that, for most of the participants, the speaking skill suffers in the online self-study environment. The speaking exercises are described as "monotonous" (M/44), "boring" (K/14), and "not beneficial" (V/56). Furthermore, "there is no flexibility of dialogue, real communication" (T/24). Kim considers the speaking activities "the same as practicing English alone, without communicating with anyone". In his viewpoint, it is "more [...] interesting when there is a dialogue, a conversation exchange with each other" (K/14). In addition, Mai feels that "the speaking part in MyELT is not very supportive. Many times, the device does not pick up the sound, so I have to say it over and over" (M/42). Lan often skipped the activities because "the activities are not responsive" (L/28).

Lack of complementarity and integration of face to face and online
In addition, the cross-case analysis shows that Kim, Tan, and Lan complained about the combination of face to face and online. In general, participants think that the combination of online and face-to-face components lacks rationality and is not effective. The combination is closed and mandatory, so it is difficult to address learners' different learning spaces because "the content is designed for the whole group of students" (T/18). Since Tan proclaimed himself a good learner, he expected to be allowed to choose what he prefers to learn, what to discard, and what he finds unnecessary. For example, Tan said that "I don't need to learn a lot of reading skills because I can read on my own time. I like to write long essays with content, but not writing in simple sentences" (T/18).
Tan assumed that it is more reasonable to combine the two pairs of skills of writing and reading, listening and speaking. This echoes Kim's viewpoint that "the structure of the lessons should be divided into groups of skills (reading and writing), (listening and speaking) for a complementary [sic]". However, "writing and speaking skills are taught in face-to-face classes separately while listening and reading skills are in Zoom classes in this course. Sometimes it's confusing. The arrangement of teaching in pairs, which is speaking and writing, listening, and reading, is convenient for implementation, but it is not really connected, lacks logic and rationality" (K/8). According to Kim, to combine the two forms of learning more effectively, the face-to-face percentage should be reduced to the maximum. The face-to-face component is designed for necessary parts, which the machine cannot replace. In fact, "if combined appropriately, this type of learning is interesting", he said (K/24).

Importance of interaction
Some participants stressed the importance of face-to-face interaction. Face-to-face interaction plays an "essential part for communication" (T/30). They viewed the interaction in their classes as positive and active. In general, the classroom atmosphere is seen as dynamic, inspiring classroom interaction and enhancing conversation exchange. For example, Lan complimented, "the class members are also enthusiastic, so when studying together, the class is very fun, and everyone interacts with each other quite a lot" (L/22). Similarly, Mai found the learning is "more useful because students have opportunity to interact with teachers and other classmates more easily" (M/54), resulting in more teacher support in "correcting and explaining in detail if anyone asks". Mai said she learned a great deal from "those corrections and explanations" (M/58). Kim shared that he found face-to-face learning effective, and thus highly appreciated it. He provided a positive experience of teacher support and feedback when he explained, "I have more interaction with the teacher and other students. When we say the wrong things or don't know how to express ourselves properly, we will be guided directly by the teacher". In his opinion, "it is necessary to have face-to-face, emotions, gestures, body language. If the exercises are more interactive for the learners, it is much better" (K/18).
Some of the participants agreed that the interaction via Zoom is limited; however, it can be effective to some extent. Lan observed her class as less interactive and "not as exciting as before [i.e. in the first weeks of the semester when there was regular face-to-face learning]" in Zoom lessons, especially speaking, which was perhaps due to "students not having the habit of interacting online" (L/8), and "opening their cameras", and students being "shy, or have little vocabulary" (L/22), and "passive" (V/96). Lan feels like she is talking to strangers. Both Tan and Kim found that the interaction via Zoom is less effective since "it is impossible for teachers to frequently observe and certainly not having enough time to visit all groups in group-work activities" (T/22). Additionally, Tan, Viet, and Kim reported preferring more "real-time interaction" as it is "more beneficial" (V/50). According to Tan, the learning "lacks interaction via group work or discussion" after the synchronous class time (T/28). Viet also misses interaction outside class time": "Teachers only explain during class, outside of class it's not convenient to ask teachers" (V/50), so "I want to have some online software that can help learners interact with each other more (V/56)".

Need for a relationship with peers and teachers
Participants underscored the relationship between teachers and students but admitted that it is difficult to achieve online. They all agreed that teachers are generally enthusiastic and friendly. For example, Mai sees her teachers are "open and joyful" (M/62). When there are students who are afraid to communicate, teachers often encourage them. "The relationship between teachers and students is neither hierarchical", or "powerful" (V/92), so the learning is "quite comfortable, not stressful" (M/62). Furthermore, the good relationship can create friendship among members in the class, so that students "find it easier to talk" (M/58), or "feel more connected", so when studying online, they "feel easier to interact" (T/26), which has "significant impact on the learning outcomes" (K/20).
However, the switch to remote learning because of COVID-19 impacted on the relationship between peers and teachers. Mai and Lan, who preferred face-to-face interaction, felt "less inclusive [sic]" in Zoom classes (L/22). Using Zalo helped to "strengthen the relationship between students and teachers" and "exchange information" (K/20). While it was perceived as useful for "administrative matters like announcement of class schedules, submission deadlines, or personal information exchange" (K/20), it also added much-needed "emotional support, making learners feel more connected, making friends, chatting with each other" (M/66).

Discussion
This study indicates six major reasons for dropping this blended English class: First, the lack of teacher support and feedback (reason 1), second, the lack of learner-centredness/autonomy (2) and, related to this desire for more feedback, the lack of interactivity in online materials (3). Further, students ask for better integration of the face-to-face and online learning components (4), and emphasize, fifth, the importance of interaction (5), and a good relationship with peers and teachers (6), which is the final reason why students dropped the class when these expectations were not met. Similar to earlier research, these reasons include student-related, teacher-related, course-related, and learning environment-related factors that are closely linked to each other.
Given that this study replicated Stracke's (2007) study, our findings necessitate a comparison with Stracke's (2007) findings and a further discussion of BLL in the Vietnamese EFL university context. Stracke (2007) identified three main reasons for dropping the blended language class in her study: "lack of support/complementarity between the two components, lack of print materials, and dislike of the computer medium" (p. 70). Although the lack of support/complementarity between the two components remains a major concern for today's Vietnamese students (reason 4), this study indicates that the lack of print materials and the dislike of the computer for language learning are no longer students' concerns. Students in this study seem to move with ease between the paper and the computer medium, whereas students in the original study missed the "conventional, traditional, and normal" materials, possibly confirming Bax's (2003) claim that CALL had not yet reached the stage of normalization (p. 23). Stracke's (2007) third reasonthe dislike, if not rejection, of the computer medium for language learningdoes not show in the current data set. This finding does not come as a surprise, given that this study was conducted more than 20 years later, and new technologies have become part of our lives and the way we learn and teach.
However, both groups of students consider the lack of complementarity between the components of the blend (reason 4) as a major reason for their dissatisfaction, which resulted in them leaving the course. This finding constitutes an urgent reminder for teachers to be aware of this issue and act upon it. Sands ' (2002) tip in this context -"Plan for effective uses of classroom time that connect with the online work"still holds but can be reformulated as "Plan for effective uses of classroom time (face to face and online) that connect with individual work". Teachers today face an even bigger challenge than their counterparts at the beginning of the millennium when trying to successfully integrate the various components of a blended language class, which combines not only face-to-face teaching with online self-study, like in Stracke (2007), but also face-to-face teaching, synchronous online teaching, self-study, both offline and online, with print and online tools and materials.
The need for teacher support, feedback, and guidance (reason 3) is another common theme across both studies. The need for "the teacher to offer the right amount of guidance and support to suit the needs of each student" (Stracke, 2007: 75) is as strong as 20 years before and can increase in times of crises such as the COVID-19 pandemic, when teachers were required to provide high levels of support and feedback when all face-to-face teaching had to move online. Software, such as MyELT, with a perceived low level of interactivity (reason 3) can aggravate the perceived lack of feedback and guidance that learners need and puts the onus on the teacher. Students need live interaction for the development of their speaking skills because the chosen LMS MyELT does not offer such interaction. Zalo seems to have filled some of this gap, but speaking activities still constitute one of the "most effective uses of classroom time" (Sands, 2002). The need for teacher guidance goes hand in hand with students' call for a more learner-centred classroom (reason 2), which might indicate that teachers might not have been able to adjust their teaching style to the new blended environment yet. G. H. Nguyen (2017) showed that the teacher's role in the Vietnamese blended context is slowly changing from knowledge provider and authority (traditional roles) to facilitator and encourager of self-directed learning (non-traditional roles). This study confirms that this change is happening, to some extent. However, teachers might need more professional development opportunities to develop the skills needed in the new blended environment for a successful transition.
The students' desire for spontaneous, live communication, preferably in the face-to-face environment but also in the online class (reason 4), is closely related to their need for relationship building (reason 5) with their teacher and classmates. Kim's statement that "going to school to meet face-to-face is definitely better" and becomes "a catalyst to create a closer relationship, through which teachers can also understand better about students' problems to help them improve" (K/20) pinpoints the close link between (face-to-face) interaction, the relationship between teacher and students, and the opportunities for teacher support during this interaction.
The change to online teaching only might have increased this student's dissatisfaction with the course to the level where they decided to leave.
To sum up, successful complementarity and integration of the blend components, the crucial role of the teacher for support and feedback within a learner-centred environment, interactive learning materials, a high level of interaction, and a good relationship between students and teachers are key for students' perception of a successful blended class. For the students in this study, it was often a combination of (some of) these factors that made them leave the course. However, there are lessons to be learned that can be applied to the further development of this and similar BLL environments for the benefit of all students in such classes. The study of these "extreme" (or outlier) cases (Patton, 2015) in the original and this replication study assisted us in gaining a better understanding of why these learners drop out. Studying learners who are not typical for the whole cohort of learners (or population) invites us to think about improvements that will provide all students in the cohort with a (more) satisfactory and successful learning experience. It is noteworthy that the lack of complementarity and integration of the blend components is one of the main reasons for students to leave the course in both the 2007 study and this current study, thus confirming the "value of replication in qualitative research" (Tuval-Mashiach, 2021: 365).
One limitation of our study is that the course delivery changed during our study due to COVID-19. Our participants were only able to attend face-to-face lessons in a classroom for the first five weeks of the course, instead of the typical 20 weeks. The reduction of the face-face component might have impacted the study's findings. However, because the reasons why the students dropped out of the blended course straddle the online and face-to-face components of the course, they are key factors to consider in any blended learning environment where the weighting of the face-to-face and online components differ.
Further, although the small number of research participants in both studies may be perceived as a limitation, the findings add to the generation of a richer and deepened understanding of the phenomenon that we investigated in this study. Future research could take a quantitative approach and involve a higher number of students or, based on the present qualitative findings, generate a survey instrument to investigate a larger group. Input from teachers could provide worthwhile complementary findings. Finally, while modest in size and scope, our study has shown the value of replicating qualitative CALL studies.

Conclusion
Our study calls for pedagogical improvements, such as teacher training and materials development, to reduce or, better, eliminate the factors that are major hurdles for successful BLL, thus increasing teacher support and feedback, interactivity in online materials, integration of the face-to-face and online learning components, and interaction and a good relationship with peers and teachers. We provide with this study some evidence for pedagogical adjustments for the delivery of current EFL BLL within Vietnam and in similar EFL contexts. Teacher training will play a significant role so that the teachers themselves can successfully and actively adjust their practice. For instance, how to successfully combine the online and face-to-face components of the course remains a challenge in a BLL environment. Sharing student views (of the 2007 study and this study) in a workshop might be a useful starting point to raise teacher awareness about the current lack of connection, leading to changes in practice and material adaptation. Further, the study indicates the need for tailored feedback in teachers' practice. Students expect personalized and specific feedback (in addition to automated feedback) so that they know which aspects of their language learning they need to focus on. Teachers might need to learn (or adjust) how to best provide learners with feedback or, perhaps better, feedforward, thus providing suggestions to students for their future learning.
Such changes can lead to higher retention rates, a reduction of costs (both financial but also emotional), an increase in student satisfaction, and a better student experience. From a methodological perspective, the study confirms that replicating a qualitative study can yield significant insights. The study's finding might well encourage other researchers to attempt a replication of their qualitative (as well as quantitative or mixed-methods research) CALL studies, thus adding to the continuous development of our field of inquiry.