Phase 1 was based on an exploratory sequential research design (Creswell, 2015), comprising an interview study (Study 1, N = 9) and a questionnaire study (Study 2, N = 212) which sought answers to RQ 1 and RQ 2. RQ 1 examined Hungarian primary and secondary school EFL teachers’ beliefs about the concepts of DI and TEDI. The studies revealed that the participants recognise the significance of DI and consider it as an important component of teaching (RQ 1.1). No significant differences were found in these beliefs based on the participants’ gender, years of teaching experience, the type of school they teach at and the region where their school is located, which suggests that DI is viewed generally positively by Hungarian EFL teachers regardless of their background variables. This accords with findings on EFL teachers’ beliefs about DI in Hungary (Zólyomi, 2022) and in other countries (e.g., Bourini, 2015; Chien, 2015; Maruf, 2023; Rovai & Pfingstorm, 2022; Sougari & Mavroudi, 2019; Tzanni, 2018), and indicates that the notion of DI is increasingly being acknowledged among EFL teachers worldwide, in line with a move from a one-size-fits-all approach to a more learner-centred view of language teaching in the past decades (Benson, 2012). The participants are also generally appreciative of the role of technology in enhancing DI practices, although it has to be noted that in the interview study there were some participants, typically those more advanced in their careers, who remained neutral or even sceptical about its relevance and effectiveness.

Furthermore, the findings suggest that the participants, in accordance with the Tomlinsonian (1999) understanding of learner diversity, interpret learner differences broadly, ranging from readiness levels (English proficiency, motivation, special education needs, learning and behavioural difficulties, students’ current emotional state), through interests to learning profiles (learning styles, intelligence preferences, gender, and socio-cultural background) (RQ 1.2). This is a notable outcome considering the enduring misconception that DI focuses exclusively on gifted and struggling learners (Whitley et al., 2019). Moreover, most participants construe learner differences as dynamic characteristics rather than as fixed traits, which suggests that they think of learners varying not only from one another but also within themselves (Tennant, 2017), which is a core principle of DI (Tomlinson, 2017). It is important to note, however, that out of all the learner differences, students’ readiness levels, most importantly, students’ English proficiency, was the most distinct learner difference that teachers consider important to address (for the results of the paired-samples t tests comparing the mean value of this learner difference with those of the other learner differences, refer to Section 4.1.2.1), in line with earlier national research (Öveges & Csizér, 2018; Zólyomi, 2022). One possible explanation for this could be that students in Hungarian public education are often placed in groups based on considerations other than proficiency levels (Öveges, 2018), which results in mixed-level classes that put proficiency levels at the forefront of teachers’ DI efforts.

Furthermore, Study 1 and Study 2 revealed a moderate degree of DI self-efficacy beliefs (RQ 1.3), which confirms the results of earlier research (Bourini, 2015; Chien, 2015; Sougari & Mavroudi 2019; Tzanni, 2018, Zólyomi, 2022) that also found rather low self-efficacy beliefs in DI compared with teachers’ otherwise positive beliefs in the approach. The factors potentially contributing to this phenomenon are multifaceted; these were examined through the analysis of the results for RQ 2.

RQ 2 investigated Hungarian primary and secondary school EFL teachers’ self-reported practices of DI and TEDI. Results indicate that teachers not only acknowledge the importance of addressing learner differences, but they also report to cater for these differences, including using technology for such purposes (RQ 2.1). Five patterns need to be highlighted in this respect. Firstly, the interview results indicate that DI is often implemented reactively rather than proactively (Tzanni, 2018) and is characterised by spontaneous adjustments rather than systematic planning, which indicates that teachers may not necessarily think about their DI practices as part of a larger DI framework (Whitley et al., 2019). Secondly, based on the results of Study 2, the differentiation of the learning environment stands out as the most frequently applied dimension of DI practice (M = 4.61, SD = 0.39) (for the results of the paired-samples t tests comparing the mean value of differentiation of the learning environment with those of the other DI dimensions, see Section 4.1.2.2), in line with some international findings (Tzanni, 2018), which could be explained by the fact that these practices (e.g., creating a safe space and nurturing a sense of community) are not exclusive to DI; rather, they encompass broader educational strategies rooted in learner-centred teaching (Ben-Yosef & Pinhasi-Vittorio, 2012). Thirdly, the emphasis on students’ readiness levels, especially their English proficiency, can be detected not only in the teachers’ beliefs but also in their practices, as both Study 1 and Study 2 (M = 4.06, SD = 0.65) revealed teachers’ preoccupation with this dimension, which may be attributed to the aforementioned mixed proficiency levels in Hungarian EFL classes (Öveges, 2018). Fourth, as for TEDI, the results of the questionnaire study suggest that there is a gap between teachers’ beliefs and practices, i.e., while most teachers recognise the affordances of technology for DI (M = 4.06, SD = 0.84), the use of technology for such purposes is significantly lower (M = 3.68, SD = 0.87, t(211) = -7.64, p < .001). As the participants reported relatively good access to ICT in their schools (M = 3.75, SD = 0.79), the gap between beliefs and practices may be more closely related to opinions and knowledge about TEDI rather than the provision of ICT facilities, which highlights the need for further research and training on TEDI in TEFL. Fifth, ANOVA tests have revealed variations among the participants’ readiness-based DI practices based on the type of institution where they work and their geographical regions. Teachers who teach both primary and secondary levels use readiness-based DI less frequently compared with those who teach exclusively in primary or secondary education, as do teachers in central Hungary compared with their colleagues in the Western and Eastern regions. While further qualitative research is needed to explore these patterns in more depth, it should be noted that these differences are relatively small, which indicates an overall similar extent of readiness-based DI practices in these contexts.

Several challenges and enablers of DI were identified in Study 1 and Study 2 (RQ 2.2). Some of these challenges are related to planning, such as increased preparation time and planning in multiple dimensions, while others pertain to the management of differentiated lessons, e.g., multi-tasking and time management constraints. Socialising students into the “workshop-style environment” (Blaz, 2016, p. 160) of differentiated classes also appears challenging for some teachers. The questionnaire study revealed that out of these difficulties, planning-related difficulties are the most concerning issues (increased preparation time: M = 4.01, SD = 1.07; planning in multiple dimensions: M = 3.92, SD = 1.06; for the results of the paired-samples t tests comparing the mean values of these two planning-related challenges with those of the other challenges, see Section 4.1.2.2), in line with the findings from other countries (Bourini, 2015; Granås, 2019; Gülsen, 2018; Lombarkia & Guerza, 2021; Sougari & Mavroudi, 2019; Tzanni, 2018). Interestingly, while uncertainties around DI methodology were mentioned in the interviews, they were deemed as the least problematic aspects in the questionnaire (M = 3.00, SD = 1.19; for the results of the paired-samples t tests comparing the mean value of methodological uncertainties with those of the other challenges, see Section 4.1.2.2). This suggests that the biggest challenges may not stem from a lack of DI knowledge and skills but rather from the demands of planning and managing differentiated lessons, which are further exacerbated by certain contextual constraints such as heavy workloads and large groups, which are often highly heterogenous in terms of language proficiency. These outcomes point toward the conclusion that, in line with earlier findings (Kálmán & Tiboldi, 2018), teachers recognise the necessity of DI, but the practical difficulties of implementation discourage them from using it on a daily basis. In light of the significance participants attach to planning-related challenges, it is understandable that access to differentiated materials (M = 4.58, SD = 0.84) and classrooms equipped with ICT tools (M = 4.41, SD = 0.87) were identified in the questionnaire study as the most important enablers (for the results of the paired-samples t tests comparing the mean values of these enablers with those of the other enablers, see Section 4.1.2.2), as they can greatly alleviate planning-related difficulties (Sougari & Mavroudi, 2019; Stanford et al., 2010; Zeng, 2020). It is important to note, however, that all the other enablers identified in the interview study, including in-service training and cooperation with stakeholders (colleagues, school administrators, parents), received mean values higher than moderate. This suggests that teachers consider several aspects as enablers of DI: they value professional development opportunities as well as the supportive power of professional learning communities at schools (De Neve & Devos, 2016).

Finally, in Phase 1, I also sought to explore the variables that influence Hungarian primary and secondary school EFL teachers’ reported use of DI and TEDI (RQ 2.3). In line with international findings (Kalinowski et al., 2024; Suprayogi et al., 2017; Whitley et al., 2019), the results suggest that teachers’ self-efficacy beliefs in DI are the most important factors predicting their use of DI, followed by perceptions of professional preparedness, including access to DI resources and training. Besides, cooperation with stakeholders was also identified as a predictor of readiness- and interest-based DI, which highlights the importance of exchanging information about students and DI methodology in making informed DI decisions. Interestingly, while general beliefs about the importance of DI do not appear to impact its implementation, beliefs about the importance of TEDI play a decisive role in motivating teachers to use TEDI, which confirms the importance of training aimed at raising awareness of the affordances of technology for DI.

The aim of Phase 2 of the research project was to take a closer look at some primary and secondary school EFL classes to identify common patterns of TEDI in TEFL (RQ 3). This phase was based on a convergent parallel mixed methods research design (Creswell, 2015) and comprised three studies: a teacher interview study (Study 3, N = 5), a classroom observation study (Study 4, with 5 teachers and 45 students altogether), and a student questionnaire study (Study 5, N = 39). While each study had its own sub-questions, their results were ultimately synthesised to answer RQ 3. In what follows, I first briefly present the findings of each study according to their corresponding sub-questions, and then I summarise the main findings for the overarching RQ 3.

Study 3 sought to explore the curricular elements of DI teachers report supporting with technology (RQ 3.1) as well as the main affordances and challenges they perceive in connection with the implementation of TEDI (RQ 3.2). As for RQ 3.1, tiered reading apps were identified as facilitators of the differentiation of the content, while vocabulary apps and interactive activity sets were seen to support the differentiation of the process. Product differentiation was reported to be enhanced with content creation tools, while technology used for creating a learning environment conducive to DI included quiz games, gamification platforms and video games. As for RQ 3.2, the participants saw several affordances and also some challenges in using TEDI. The main affordances for students include a greater degree of choice in the learning process, the enhancement of self-paced learning, the motivational effect of ICT tools, task privacy, and the chance to develop ICT skills. Some teacher-related benefits were also identified, such as the alleviation of workload, easier classroom management, and the opportunity for quick diagnostic assessment. The challenges of TEDI pertained to the difficulties of finding the right balance for using technology, learning how to use ICT tools as well as having to devise a plan B in case there is no internet access in the classroom. Overall, the results suggest that the participants have dominantly positive views about TEDI, but they also demonstrate awareness of the potential pitfalls of technology (over)use, which indicates a principled approach towards the affordances of technology for DI.

Study 4 focused on how the teachers’ reported strategies are put into practice, i.e., what curricular elements of DI are supported with technology in their observed practices (RQ 3.3) and what affordances of technology for DI can be identified in these practices (RQ 3.4). Regarding RQ 3.3, the results converge with and complement the findings of Study 3 insofar as tiered reading apps and online learning resources with scaffolding potential were identified as content differentiation tools, vocabulary apps and interactive activity sets were used for process differentiation, products were differentiated with the help of content creation tools, while the learning environment was found to be shaped by quiz games and gamification platforms. As for RQ 3.4, in line with the findings of Study 3, the main affordances of technology identified for DI were self-paced learning, student choice, privacy (including both task and result privacy), and increased student motivation and engagement.

The aim of Study 5 was to explore the students’ perspective of the examined TEDI practices, more specifically, to examine the extent to which students perceive TEDI as responsive to their readiness levels, interests, and learning profiles (RQ 3.5) and the relationships between these perceptions and the variables of motivated learning behaviour, language learning experience, and self-efficacy beliefs (RQ 3.6), i.e., ID variables that have been shown to improve in TEDI contexts (e.g., Hustinx et al., 2019; Vargas-Parra et al., 2018). As for RQ 3.5, students perceived TEDI as responsive to their individual needs, with all three dimensions of TEDI perceptions having a mean value higher than moderate. It is also important to note that students’ motivated learning behaviour, language learning experience and self-efficacy beliefs all had a mean value higher than 4.4 on a 5-point scale.

Correlation and regression analyses were carried out to test if there were any relationships between these variables. Perceptions of learning profile-based TEDI showed a weak positive correlation with language learning experience, while interest-based TEDI perceptions were found to have a moderate positive influence on language learning experience, which suggests that students’ language learning experience tends to be of higher quality when students perceive technology-enhanced tasks to be in line with their interests. Besides, results indicated that readiness-based TEDI perceptions had a moderate positive impact on self-efficacy beliefs, which suggests that technology-enhanced tasks that are perceived by students to be responsive to their readiness levels have the potential to strengthen their confidence in their ability to perform these tasks successfully. The link between readiness-based DI and self-efficacy beliefs has been addressed in theory (e.g., Tomlinson, 2017) and in studies on the differentiated teaching of certain subjects (e.g., Hood, 2012; Lai et al., 2020), however, to the best of the author’s knowledge, this is the first time it has been statistically proven in the TEFL context. As language teachers’ DI practices in the Hungarian public education primarily focus on addressing readiness levels (Öveges & Csizér, 2018; Zólyomi, 2022; Section 4.1 of this book), the support offered by certain ICT tools in this respect appears to be particularly noteworthy.

The synthesised analysis of the results of Studies 3, 4, and 5 has revealed two overarching patterns in the examined TEDI practices (RQ 3) (for a visual summary of these findings, refer to Figure 9 in Section 4.2.4 and Appendix Q). Firstly, results suggest that there is a wide range of ICT tools available for EFL teachers to differentiate the content, the process, and the product according to their learners’ readiness levels, interests, and learning profiles, and to create a learning environment conducive to differentiated learning (see a list of the apps in Figure 10 below, with an extended list including URL links in Appendix R).

These tools can alleviate the teaching workload in several respects, including planning, classroom management and assessment. They provide differentiated resources, can give immediate feedback to students, and generate detailed reports of student performance that teachers can use for formative assessment, which is a cornerstone of DI (Blaz, 2016). Equally important is that students perceive the activities supported with these tools to be resonating with their needs, as they reported strong perceptions of TEDI being responsive to their readiness, interests, and learning profiles. This is noteworthy because, as Tomlinson (2017) argues, it is essential for students to see evidence that they are “on the teacher’s radar” and that “the teacher understands their development and plans with their success in mind” (p. 5).