With the global dominance of English as the academic lingua franca (Hyland, 2009, 2022), university students and researchers increasingly need to improve their knowledge of this language to read published studies in their fields and also to publish their research in international journals (Li and Flowerdew, 2020). Accordingly, along with the proliferation of English for Academic Purposes (EAP) programs around the world (Hyland, 2006, 2013), developing university students’ academic literacy is attracting increased attention (Muresan and Orna-Montesinos, 2021; Li, 2022). One critical aspect of academic literacy is learning and using academic words (Coxhead, 2000). Defined as those words that are used with higher frequency in the discourse of academia (rather than non-academic discourse; Gardner and Davies, 2014), academic vocabulary is employed extensively for writing about abstract ideas and processes in science (Nagy and Townsend, 2012). These words are also used extensively for structuring and framing rhetorical organization of academic texts (Paquot, 2010; Coxhead, 2019). Recent corpus-based investigations into academic discourse showed that academic words constitute a considerable proportion of academic texts such as research articles and textbooks, with coverage ranging from 6 to 14% of all words depending on different academic word lists (Coxhead, 2000; Browne et al., 2013b; Gardner and Davies, 2014). Some widely used academic words in English include repertoire, obtain, distribution, parameter, aspect, dynamic, impact, domain, publish, and denote (Browne et al., 2013b).

Scaffolding the processes involved in learning academic vocabulary among English as a Foreign Language (EFL) students is essential for some reasons. First, previous research indicated that learning vocabulary and developing lexical competence in a foreign language is a long-term process that takes many years (Webb and Chang, 2012; Rahmani et al., 2022; Zakian et al., 2022). Accordingly, there is a need for pedagogical interventions to facilitate vocabulary knowledge development among EFL learners (Webb and Nation, 2017). Second, learning (and using) academic words are associated with a considerable learning burden for EFL university students (Evans and Morrison, 2010, 2011; Xodabande et al., 2022; Boroughani et al., 2023). In this regard, there is a growing need for a systematic focus on covering these words in EAP programs regardless of the learning context (Coxhead, 2018, 2019; Xodabande and Boroughani, 2023). Additionally, the expanding body of knowledge in corpus-based studies of research articles as the pre-eminent genre in academic discourse has shown the significant role and the importance of academic words in scientific communication (Martínez et al., 2009; Lei and Liu, 2016; Xodabande et al., 2022). It has also been argued that using academic words is closely related to professional identity construction in writing for publication (Hyland and Tse, 2007; Green and Lambert, 2018; Roesler, 2021). Consequently, research on identification and teaching academic vocabulary remained an active area of inquiry, being mainly concerned with addressing pedagogical challenges in EAP programs (Coxhead, 2019).

Over the past two decades, significant expansion in digital technologies provided us with new tools and resources to address EFL university students’ vocabulary learning needs (Lin and Lin, 2019; Burston and Giannakou, 2021; Hao et al., 2021; Yang et al., 2021; Yu and Trainin, 2022). One main line of research within this literature investigated the learning outcomes of using mobile devices for vocabulary learning. Accordingly, the findings from a large number of studies indicated that mobile-assisted learning is generally more effective compared to the learning conditions involving traditional materials (Mahdi, 2017; Lin and Lin, 2019). Moreover, accumulated empirical evidence in this area suggests that mobile-assisted vocabulary learning effectively develops receptive and productive knowledge of target words (Li and Hafner, 2022; Xodabande et al., 2022). Additionally, the related studies pointed to both short- and long-term learning impacts of mobile-assisted instruction (Xodabande and Atai, 2022). Considering the effectiveness of flashcards (or word cards) in fast and effective vocabulary learning (Nakata, 2019; Lei and Reynolds, 2022), mobile-assisted academic vocabulary learning via digital flashcards is gaining popularity (Dizon, 2016; Xodabande et al., 2022; Xodabande and Atai, 2022; Yüksel et al., 2022; Boroughani et al., 2023; Xodabande and Boroughani, 2023). Collectively, these studies showed that digital flashcards provide university students with affordances for augmenting their vocabulary knowledge more systematically and beyond the physical and temporal restraints of the classrooms. Nevertheless, although most studies were conducted in self-regulated and beyond the classroom learning environments, scant attention has been paid to the contribution of mobile-assisted vocabulary learning on university students’ self-regulatory capacity (Tseng et al., 2006; Tseng and Schmitt, 2008; Fathi et al., 2018; Lei et al., 2022; Teng et al., 2022). As self-regulatory capacity is a key factor in strategic vocabulary learning, research in this area has considerable potential to improve second language literacy (Boroughani et al., 2023).

In educational psychology, self-regulated learning (SRL) theory is primarily concerned with factors and processes such as metacognition, motivation, and strategic action that are significantly important in learning pre-specified content (Zimmerman, 2002; Brenner, 2022). Additionally, helping students to become self-regulated learners is now considered an essential goal for modern educational systems (Zimmerman, 2008). Relatedly, SRL is gaining increased recognition as a defining component in language learning (Zhang et al., 2019; Teng and Zhang, 2020). Research focusing on the relationship between vocabulary learning and SRL among EFL students indicated that their capacity to engage in SRL contributes significantly to developing their lexical competence (Choi et al., 2018; Fathi et al., 2018; Şahin Kızıl and Savran, 2018; Chen et al., 2019). For example, Chen et al. (2019) investigated the role of a vocabulary learning application with a mechanism for self-regulated learning that aimed to help learners to enhance their SRL abilities, learning performance, and motivation. The study revealed that those learners who used the SRL mechanism attained better learning outcomes and improved motivation. Moreover, focusing on technology-assisted learning environments, Şahin Kızıl and Savran (2018) developed an instrument for measuring the self-regulatory capacity of EFL students for vocabulary learning. The study indicated that self-regulated capacity for using technology might be a valid predictor of EFL students’ success in learning vocabulary via a wide range of information and communication technologies.

Moreover, some studies investigated the impacts of mobile-assisted learning on language learners’ self-regulatory capacity. In this regard, Kondo et al. (2012) explored the impacts of mobile-assisted learning on Japanese university students’ self-regulated learning. The findings indicated that using mobile devices for language learning contributed to increased motivation among learners and improved their self-regulatory capacity. In another study, Zheng et al. (2018) developed a mobile-based self-regulated system for supporting university students’ self-regulated learning skills. The study findings revealed that the developed system significantly improved the students’ skills for self-regulated learning without much impact on the cognitive load associated with learning tasks. Furthermore, Ferreira (2014) examined young English language learners’ self-regulated learning in a technology-supported environment. The findings of the study showed that those students who received technology-supported training had better performance in vocabulary learning tasks. Accordingly, the existing literature suggests that not only self-regulatory capacity is a good predictor of success in technology-assisted vocabulary learning, the use of digital devices for vocabulary learning also impacts language learners’ self-regulatory capacity.

Despite this recent interest in exploring various aspects of self-regulated vocabulary learning among EFL learners, a number of gaps in the literature foreground the need for further empirical studies. First, the application of SRL theory to language education is a relatively recent phenomenon (Kim et al., 2015; Teng, 2022). The limited evidence in this area makes it difficult to see how such learning mechanisms contribute to developments in different language skills including second language vocabulary learning (Şahin Kızıl and Savran, 2018). Second, although research on mobile-assisted vocabulary learning expanded considerably (Lin and Lin, 2019), utilizing the affordances provided by mobile platforms for scaffolding academic vocabulary learning as a key factor in academic literacy development remained less explored (Xodabande and Atai, 2022). Additionally, considering the importance of vocabulary learning strategies in long-term and effective vocabulary knowledge development for EFL students (Pavii Taka, 2008), the contribution of well-established strategies such as digital flashcards for enhancing the self-regulatory capacity of EFL learners remained less explored (Fathi et al., 2018; Nakata, 2019; Lei et al., 2022; Lei and Reynolds, 2022). The present study aimed to address the abovementioned gaps by answering the following research questions:

As mentioned in the previous section, before implementing the treatments, the participants in both groups were tested using the NVLT (McLean and Kramer, 2015) and Self-regulating Capacity in Vocabulary Learning Scale (Tseng et al., 2006; Ziegler, 2015). The results of the t-test comparing the two groups based on mean scores pointed to no significant difference in their pre-existing vocabulary knowledge, t (52) = 0.15, p ≤ 0.886 (experimental = 66.64, SD = 9.84; control = 66.19, SD = 11.81). Accordingly, the sample was homogenous regarding their vocabulary knowledge. The results of the descriptive statistics for the scores obtained on self-regulatory capacity (SRC) and academic vocabulary knowledge test (VKT) are summarized in Table 1. As shown below, the observed differences in the scores were not much noticeable in the pre-tests. However, the results obtained on the post-tests pointed to considerable differences in the participants’ performances in the experimental and control learning conditions.

As data collected for the study included the experimental and control groups’ scores on academic vocabulary test and their self-regulatory capacities at two times (i.e., pre-test and post-test), the results were analyzed for within-subjects and between-groups differences. Table 2 shows the results obtained for the tests of within-subjects effects. Accordingly, data analysis indicated that developments in the participants’ self-regulatory capacity (F (1, 52) = 6.98, p ≤ 0.011, η_p² = 0.118) and academic vocabulary knowledge (F (1, 52) = 140.92, p ≤ 0.001, η_p² = 0.73) were significant from pre-test to post-test. These results indicated that all participants improved their self-regulatory capacity and academic vocabulary regardless of the treatments (i.e., digital flashcards and wordlists) they received. However, the analysis also pointed to significant interaction effects between time and group variables. These significant interaction effects mean that the developments in the experimental and control groups’ self-regulatory capacity and academic vocabulary knowledge were different.

Considering significant interaction effects reported in Table 2, the data were analyzed for between-groups differences (Table 3). In this regard, the findings revealed that before the treatments, there were no significant differences in the participants’ self-regulatory capacity for vocabulary learning (F (1, 52) = 1.064, p = 0.307, η_p² = 0.020); and their knowledge of academic vocabulary (F (1, 52) = 0.887, p = 0.351, η_p² = 0.017). However, the observed differences between the groups were significant after the treatments. Accordingly, the two groups performed differently with respect to their self-regulatory capacity for vocabulary learning (F (1, 52) = 20.85, p ≤ 0.001, η_p² = 0.286); and knowledge of academic words in English (F (1, 52) = 33.224, p ≤ 0.001, η_p² = 0.390). More specifically, the participants in the experimental group outperformed those in the control group in learning academic words and developing their self-regulatory capacity for vocabulary learning. The effect sizes of the differences were large based on criteria proposed by Cohen (1988).

Figure 1 provides a visual representation of the estimated marginal means for self-regulatory capacity scores. As shown below, although the mean scores for the experimental (DFs) and control (wordlist) groups were close to each other before the treatments, the differences were significant in the post-test. Additionally, both groups improved their capacity for self-regulated vocabulary learning; however, using DFs resulted in more improvements.

Additionally, Figure 2 visually represents the estimated marginal means for vocabulary test scores. In this regard, the existing differences in the academic vocabulary knowledge of the participants in the experimental (DFs) and control (wordlist) groups were not much noteworthy before the treatments (see Table 2). However, the resulting differences were significant in the post-test, and students who used DFs scored considerably higher than the control learning condition.

The first research question examined the contribution of mobile-assisted academic vocabulary learning with digital flashcards as a pedagogical intervention for improving university students’ academic literacy. The findings indicated that although both treatments effectively scaffolded vocabulary learning (Table 2), the participants who used digital flashcards outperformed those in the control group that used traditional materials (i.e., wordlists, Table 3). Consequently, the study provided empirical evidence for the effectiveness of mobile-assisted academic vocabulary for university students. The findings agree with earlier studies that reported similar results (Dizon, 2016; Xodabande et al., 2022; Xodabande and Atai, 2022). The relative effectiveness of mobile-assisted learning might be explained in light of the following considerations. First, digital flashcards provided the participants with a more effective strategy for vocabulary learning. More specifically, the spaced repetition feature enabled them to have multiple encounters with the target words, and such exposure to form-meaning connections facilitated learning academic words (Webb and Nation, 2017; Nation, 2022). Second, learning with digital flashcards involved more retrieval efforts on the part of the participants in the experimental group compared to the control group. As highlighted by previous studies, such mechanisms contribute significantly to improved learning outcomes (Li and Hafner, 2022; Xodabande et al., 2022). Third, it has been observed that integrating digital technologies into language education results in enhanced motivation and learner engagement due to the inherent motivational potential of using technology (Stockwell, 2013; Xodabande and Atai, 2022). Consequently, given the determining role of motivation in language learning success (Dörnyei and Ushioda, 2010), this factor might have contributed to the improved performance of digital flashcards users.

The second research question concerned the impact of digital flashcards on university students’ self-regulatory capacity for academic vocabulary learning. The findings indicated that those participants in the experimental group learned more academic words and developed more self-regulatory capacity for vocabulary learning (Table 3; Figure 1). This finding is in line with the studies that found a similar relationship between mobile-assisted vocabulary learning and improvements in self-regulated learning capacity (Choi et al., 2018; Fathi et al., 2018; Lei et al., 2022). This outcome might have resulted from some factors. First, learning academic words with digital flashcards facilitated the development of some basic self-regulation skills, such as setting realistic goals, managing time and learning resources, and selecting the best strategies for achieving the goals (Zheng et al., 2018; Lei et al., 2022). Second, learning with digital flashcards impacted the participants’ commitment control more effectively than learning from wordlist and accordingly facilitated managing more favorable expectations through learning words in specific sets (Tseng et al., 2006). Third, as highlighted above, digital flashcards bring inherent motivational impacts to vocabulary learning. Considering the role of emotion control in the self-regulatory capacity for vocabulary learning (Ziegler, 2015), it has been argued that increased motivation boosts positive emotionality and minimizes the impacts of negative emotions (MacIntyre et al., 2019). Finally, observed changes in the participants’ self-regulatory capacity might be due to increased metacognitive control over vocabulary learning resulting from digital flashcards (Teng and Zhang, 2022). As mobile-assisted learning provided the participants with affordances to monitor their learning progress and evaluate their performance, they developed more capacity for self-regulated vocabulary learning.

The findings have some implications for teaching academic words and improving EFL university students’ academic literacy. First, as the study indicated, using digital flashcards and mobile-assisted learning effectively result in substantial vocabulary gains. Considering the crucial role of academic vocabulary in scaffolding university students’ literacy development (Coxhead, 2019) and the fact that learning such words is associated with a significant learning burden (Evans and Morrison, 2011), EAP programs might benefit significantly from the integration of mobile-assisted learning into their curricula and instructional processes to address vocabulary learning needs. Second, vocabulary learning via digital flashcards seems to be a practical approach to extending learning beyond the classroom. Accordingly, various affordances provided by mobile devices for moving the vocabulary learning activities to anytime and anyplace is specifically noteworthy for EAP teachers (Xodabande and Atai, 2022). Additionally, with the growing importance of self-regulated learning in language education, academic vocabulary learning with digital flashcards might be considered as a pedagogical innovation that facilitates long-term academic literacy development as it builds university students capacity to learn autonomously and to take more responsibility with respect to their learning needs. Finally, as using innovations and technologies for language learning is inherently motivating (Stockwell, 2013), mobile-assisted academic vocabulary learning provides EAP programs with new possibilities to sustain and support university students’ engagement with the learning content. Collectively, these implications highlight the affordances of mobile-assisted vocabulary learning as one of the most recent developments in educational technology. Tailoring this technology to EFL university students’ learning needs through developing their academic vocabulary contributes to the success of EAP programs and helps build their professional identity.

The original contributions presented in the study are included in the article/supplementary material, further inquiries can be directed to the corresponding author.

Ethical review and approval was not required for the study on human participants in accordance with the local legislation and institutional requirements. The patients/participants provided their written informed consent to participate in this study.

All authors listed have made a substantial, direct, and intellectual contribution to the work and approved it for publication.

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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