The notion of optimism has its roots in Bandura's social intellectual hypothesis, Coleman's community principal hypothesis, and Seligman's academic optimism. It is a novel construct introduced in PP research that strongly and directly influences teachers' pedagogy and students' achievement. Optimism comprises collective efficacy, faculty trust, and academic emphasis (Asgari and Rahimi, 2014). It is an intrinsic attribute referring to a person's positive expectation about the future despite the current difficulties and setbacks (Carver and Scheier, 2002). More specifically, it is a personal proclivity to believe that one will normally experience good events in life and escape bad outcomes. In EFL contexts, optimism refers to a teacher's belief that he/she can improve students' learning by highlighting academics and learning, trusting parents, and students to get involved in the process, and believing in his/her capacity to defeat problems and resiliently react to failures (Hoy et al., 2008). Optimistic EFL teachers stay strong and determined in the face of challenges and adversities and envision positive and desirable outcomes for their actions (Pathak and Lata, 2018). Consequently, they do their best to execute instruction perfectly ignoring the setbacks.

Three dimensions have been proposed for teachers' optimism including academic emphasis, faculty trust, and collective efficacy (Figure 1). Academic emphasis concerns teachers' enacted behavior inspired by their beliefs in generating learning and academic success in students via an optimistic classroom culture. Faculty trust refers to teachers' confidence in students and parents to get engaged in the learning process. This involvement leads to establishing high academic standards for learning endorsed and favored by both students and parents. As the last dimension, collective efficacy refers to teachers' belief in their ability to execute instruction efficiently and cause student achievement (Hoy et al., 2006; Hoy and Miskel, 2013). It is essential to note these dimensions are in a reciprocal and interactional relationship each influencing and shaping the other two.

Teacher commitment is a mental association that a person creates between his/her beliefs and work in a way that the whole faithfulness is directed toward his/her profession (Lu, 2021). It is a pivotal element of successful teaching as it helps in establishing a learning environment where the students' achievement level and performance are improved significantly (Altun, 2017). As put by Sarikaya and Erdogan (2016), commitment manifests itself when a teacher feels and has a full obligation to take extra duties and tasks in his/her work so that positive outcomes are accomplished. Hence, it can be argued that teacher commitment in L2 education refers to a teacher's capability to accept a school's objectives with passion and energy, mentally identifies him/herself with the job, takes operational steps to improve instruction, and forms an emotional connection to the profession. It encompasses a sense of obligation to the school, students, vocation maintenance, proficient knowledge base, and teaching career (Crosswell and Elliott, 2004; Han, 2021b). As a fundamental core and a well-spring of instructional excellence/quality, teacher commitment improves students' achievement and participation, teachers' work performance, and school's quality. So, it is critical to establish, maintain, and promote this psycho-emotional variable in EFL teachers worldwide.

There exists a number of characteristics for committed teachers. They basically make the constant attempt and have a desire for greatness, have strong interpersonal communication abilities, care about instruction progress, learning, and achievement (Altun, 2017). Moreover, committed teachers incline to consider students' needs and wants, know how to motivate students, can urge learners to participate in class activities, tend to fulfill school's short-term and long-term goals (Wang and Guan, 2020; Lu, 2021). Last but not the least, they are dedicated to faculty and its improvement, establish a positive learning climate, are mentally connected to their work, and are passionate about taking extra steps to promote teaching and learning cycle (Sarikaya and Erdogan, 2016).

The concept of work engagement is grounded in work engagement theory that highlights the importance of personal enjoyment, vitality, and enthusiasm in work which drive the person forward in his/her job performance (Schaufeli et al., 2009; Han and Wang, 2021).

It is a mental state pertaining to work that encompasses vigor, dedication and absorption (Schaufeli et al., 2009; Wang and Guan, 2020). It is the counterpart of burnout in that while burnout has harmful impacts on one's work performance, work engagement is a positive side of work that positively influences the person and the organization (González-Romá et al., 2006). In simple words, work engagement concerns how an individual dedicates time and energy to accomplish a task that is influenced by many internal and external factors (Han and Wang, 2021). According to Field and Buitendach (2012), teachers' work engagement is a positive emotional state inside the person that reflects their work life, performance, gratification, and quality. As pinpointed by Schaufeli et al. (2002), the construct has three dimensions of vigor which concerns having the willingness, energy, resilience, persistence in work, dedication that is a sense of work inspiration, enthusiasm, importance, pride, and challenge, and absorption which refers to being deeply involved in the work in such a way that one vehemently relishes working relentlessly as time passes (Figure 2). Furthermore, it is worth noting that the notion of work engagement is different from workaholism in the sense that engagement is a positive feature that generates positive outcomes, whereas workaholism is a negative trait does that causes harm and leads to job burnout. Based on these dimensions, it can be claimed that teachers' level of optimism and commitment is strongly related to and influences the quality and extent of work engagement in L2 teaching which has largely been ignored in the literature.

In the available literature of work engagement in language education, the construct has been studied and associated with a number of factors and variables including burnout, self-efficacy, reflection, emotion-regulation strategies, psychological well-being, positive emotion, social support, resilience, job resources, and identity (e.g., Minghui et al., 2018; Shirazizadeh and Karimpour, 2019; Van Der Want et al., 2019; Greenier et al., 2021; Han and Wang, 2021). It has been shown that teachers' inner emotions like being optimistic and confident of their teaching abilities will influence their engagement level at work (Minghui et al., 2018). Likewise, research shows that teachers' optimism and commitment can reflect themselves in their occupational performance, satisfaction, problem-solving, and engaggenent (Field and Buitendach, 2012; San and Tok, 2017; Kristiana et al., 2018; Han, 2021a). Other correlates have been approved in the previous studies mentioned earlier in this review article. Yet, there are still many other related variables such as agency, willingness to communicate (WTC), and interpersonal communication skills which need empirical investigations to make their linkage to work engagement more vivid.

In this mini-review study, it was argued that EFL teachers' optimism and commitment are directly and strongly associated to their quality and degree of work engagement. It was also maintained that each of these constructs has different dimensions influenced by numerous internal and external factors in L2 education. This has led to the conduct of various studies on each of the variables and their contribution to successful instruction and learning. As a result, the present review can offer a number of practical implications for EFL teachers, teacher educators, program designers, school principals, and L2 researchers. The study can be beneficial for EFL teachers in that it can raise their awareness and understanding of positive emotions and their role in teaching and learning processes. Moreover, EFL teachers will realize that their optimism and commitment to teaching can make a meaningful difference in their teaching quality as well as students' learning. Likewise, teacher trainers can use the ideas in this review and devise training courses for novice and experienced EFL teachers and teach different strategies to improve and boost EFL teachers' positive emotions, especially their optimism and commitment to teaching aside from pedagogical and methodological concerns. Additionally, program designers can offer workshops, seminars, and webinars to EFL teachers in which various ways of being optimistic and committed to instruction are taught professionally. School principals as important agents in education can also use the propositions made in this study and assist EFL teachers in being optimistic, committed, and engaged in work via providing a positive, democratic setting which has all the required facilities for teachers to execute instruction efficiently. Finally, L2 researchers can take advantage of this review article in that they can run replicate and complementary research focusing on the existing gaps in this line of inquiry. As stated, the majority of the studies on optimism, commitment, and work engagement are correlational and one-shot. Hence, future scholars can conduct qualitative and mixed-methods studies to make the picture more comprehensive. The role of cultural factors has also been ignored in this line of research, so future studies are recommended to explore the effect of culture on these three constructs. Furthermore, the developmental trajectories of each of these variables can be studied using portfolio, diary, and journal writing by EFL teachers of various experiences. In a similar manner, the possible impact of teachers' interpersonal communication skills such as stroke, credibility, clarity, care, confirmation and the like on EFL teachers' degree of optimism, commitment, and work engagement can be interesting avenues for research. Finally, the relationship between teachers' identity, agency, demographic factors, and the three variables presented in this study can also be a direction for future research. These ideas show that working on these three variables is still fresh in EFL contexts and more attention called for by L2 researchers all around the globe.