Responding to the Need for Re-Conceptualizing Second Language Teacher Education : The Potential of a Sociocultural Perspective

This paper aims to engage with and respond to recent calls in the literature for a unifying theoretical framework to understand second language teacher education (SLTE). It critically reviews the major conceptualizations of SLTE in relation to the key conceptualizations of second language (L2) teaching. The review identifies shortcomings in traditional perspectives on L2 teaching and SLTE and the need to re-conceptualize SLTE as a field. A recent re-conceptualization of SLTE is seen through the shift towards a social constructivist perspective, a redefinition of the knowledge base, research that responds to the epistemological shift, and a sociocultural perspective on SLTE. The existing literature shows that although there is now a growing body of research that looks into the various dimensions of SLTE, few studies have gained a comprehensive and systematic view of the complexities of SLTE. The paper argues that a sociocultural perspective, especially a combination of Vygotsky’s genetic method and Engeström’s proposal of the third generation of activity theory, has become a powerful way of understanding L2 teacher learning, which corresponds to the need for a re-conceptualization of SLTE. This paper calls for more research using a sociocultural framework to enrich its knowledge base.


The Need for a Unifying Conceptualization of SLTE
One of the limitations of the literature on teacher education in general and SLTE in particular is the lack of a coherent, shared theory of learning as a lens for a common understanding of teacher education, and this needs to be urgently addressed.Examining contemporary empirical research on teacher education, Borko, Liston, and Whitcomb (2007) noted that the central limitation of interpretive research, which "seeks to describe, analyze, and interpret features of a specific situation, preserving its complexity and communicating the perspectives of participants" (p.4), is "the lack of shared conceptual frameworks and designs, which makes it a challenging task to aggregate findings and to draw comparisons across studies, even when those studies are of similar phenomena" (p.5).Given that interpretive research has come to be seen as a better suited paradigm for understanding the complexities of language teacher education, and the field has undergone a shift towards an interpretive paradigm (Johnson, 2009), its limitation mentioned above is characteristic of a major proportion of current research in the field and therefore worth attention.This is in evidence through an extensive review of research on language teacher learning (Borg, 2006) where it is found that in order for the field to move forward, it is imperative to have a broader, coherent conceptual framework to organise our current understanding of teachers' thinking, knowing, and doing.Borg (2006) succinctly elaborated on the benefits of having such a conceptual framework as follows: [A unifying framework] militates against the accumulation of isolated studies conducted without sufficient awareness of how these relate to existing work; it reminds researchers of key dimensions in the study of language teacher cognition; and it highlights key themes, gaps and conceptual relationships and promotes more focused attention to these.(p.284) Sharing the aforementioned concern, Barkhuizen and Borg (2010) remarked in an editorial on researching SLTE that although there have been significant advances in research on SLTE, it is "not yet characterised by a well-defined research agenda and a programmatic approach to research" (p.237).Similarly, according to Johnson and Golombek (2003): Although the field of L2 teacher education has a growing body of research characterizing what teacher learning is and where it takes place, it has yet to embrace a coherent theory of learning upon which to ground a common understanding of what the internal cognitive processes of teacher learning actually are.(p.728) In addition, with a particular focus on comparative contexts, Burton (1998) argued that there remains a missing link in SLTE research that serves as a shared reflective framework for researchers, teachers, and teacher educators to theorise and compare practice across contexts.
The authors mentioned above appear to agree on the absence of a coherent theoretical framework to underpin research in SLTE and the need to embrace such a framework to move the field forward.This paper aims to trace back the origins of the need for such a unifying theory and provide a response to it by engaging with the shift to a sociocultural perspective on SLTE and its implications for research on L2 teacher learning.It begins by reviewing the most prominent traditional conceptualizations of language teaching and how they inform different views on second language teacher education.In so doing, it also problematizes these traditional perspectives on SLTE, justifies the need for the field to be re-conceptualized, and reviews the current trends in the field in support of the re-conceptualization of SLTE.The paper then argues for the potential of a sociocultural perspective, especially the concepts of genetic method (Vygotsky, 1978(Vygotsky, , 1981) ) and activity theory (Engeström, 1987(Engeström, , 2001) ) in researching L2 teacher learning.

Traditional Conceptualizations of Language Teaching
The field of SLTE has seen dramatic shifts in the way language teaching is conceptualized.These epistemological changes have contributed to defining the various approaches to SLTE and informed its practice.There have been three major ways of categorizing conceptions of language teaching in the SLTE literature.This section reviews major conceptualizations of language teaching following the categorizations by Wallace (1991), Freeman andRichards (1993), andFreeman (1996).
According to Wallace (1991), there are three general conceptualizations of language teaching: (1) the craft model, (2) the applied science model, and (3) the reflective model.In the craft model of language teaching, "the master teacher told the students what to do, showed them how to do it and the students imitated the master" (Stones & Morris, 1972;cited in Wallace, 1991, p. 6, original emphasis).This conceptualization of language teaching closely reflects a behavioural understanding of the language learning process, which underplays the various kinds of knowledge, skills and beliefs that students bring to the table.The applied science model, on the other hand, "derives its authority from the achievement of empirical science" (Wallace, 1991, p. 8).This model considers teaching as "merely instrumental in its nature" (Wallace, 1991, p. 8) where teachers can solve teaching problems by applying empirical research, which might be done by scholars in other contexts, to their practices.Finally, in the reflective model of teaching teachers gain knowledge through engagement in teacher education courses and their daily experiences, reflect on these experiences, and recursively apply their knowledge to practice and so on (Wallace, 1991).Freeman and Richards (1993) described three categories of language teaching conceptions, including (1) scientifically based conceptions, (2) theory-and value-based conceptions, and (3) art/craft conceptions.According to Freeman and Richards (1993), the scientifically based conceptions are further divided into three subgroups, namely "those which operationalize learning principles, those which follow a tested model, and those which are based on what effective teachers do" (p.195).These conceptions depend on empirical research in L2 learning, effective teaching models, effective teacher practices and the applications of the empirical research findings to language teaching.This group of conceptions shares the assumptions with Wallace's (1991) applied science model and Freeman's (1996) cognitive model of language teaching discussed below.
The second category identified by Freeman and Richards (1993), the theory-and value-based conceptions of teaching, is comprised of 'teaching based on theory' view and 'teaching based on values' view.This classification was developed by taking Zahorik's (1986) general conceptual classification of teaching as a starting point and analysing empirical evidence from the field in relation to the conceptual framing.The theory-based teaching methods rely on rational justification of "what ought to work" (Zahorik, 1986, p. 22) rather than on empirical research.On the other hand, values-based teaching is derived from the values or beliefs about "what is normally right" (Zahorik, 1986, p. 22).It promotes teaching that is "morally, ethically, or politically advantageous" as well as "science, rationality, and theoretical coherence" (Freeman & Richards, 1993, p. 203).
The third category, art/craft conceptions of teaching, views teaching "as an art or a craft, as something which depends upon the individual teacher's skill and personality" (Freeman & Richards, 1993, p. 205).As Freeman and Richards note, teachers have both freedom to use their personal skills and responsibility to assess specific classroom situations in order to solve teaching problems.However, the art/craft conceptions of language teaching do not deny the importance of teachers' professional knowledge and skills.In addition, teachers' self-assessment, reflection, and analysis skills are of prime importance in this view of teaching.
It is interesting to note that while Freeman and Richards (1993) and Wallace (1991) used the common term 'craft', their description of the craft model shows remarkable difference in their understanding.In Wallace's (1991) view of the craft model, the teacher is a 'master' who tells students what to do and how to do it without paying attention to what the students have to contribute.In contrast, Freeman and Richards (1993) viewed teachers in the craft language teaching model as having responsibility to analyse the classroom situations, including learner factors, to inform their classroom decisions.For Freeman and Richards, teaching in the art/craft model depends much on the teacher's evaluation of the context and reflection on their practices, rather than being a one-way teacher-to-learners or transmission process.It appears that Freeman and Richards' (1993) conceptualization of the art/craft model of language teaching shares some common ground with Wallace's (1991) view of the reflective model.
Another categorization presented by Freeman (1996) included three views of teaching: (1) the behavioural view, (2) the cognitive view, and (3) the interpretive view.Firstly, the behavioural view is commonly described as a 'teaching as doing' model, which emphasises teacher skills in what they do.This model is similar to the craft model of teaching identified by Wallace (1991).Secondly, the cognitive view, which is also known as the 'teaching as thinking and doing' model, places a focus on what teachers know and do, and how they do it.It corresponds to Wallace's (1991) craft model and applied science model of language teaching.Finally, the interpretive view, which Freeman (1996) termed the 'teaching as knowing what to do' model, emphasises the reasoning of what teachers do in different contexts.This corresponds broadly to the reflective model of language teaching identified by Wallace (1991).

Traditional Conceptualizations of SLTE
The various conceptualizations of language teaching reviewed in the previous section contribute immensely to the epistemological approaches to SLTE.This section discusses the conceptualizations of SLTE in relation to the views of language teaching aforementioned.It focuses on three major traditional conceptualizations of SLTE: the behaviourist, humanistic, and positivist perspectives.It also problematizes these conceptualizations and argues that there is a need for re-conceptualizing SLTE.
Behaviourism is one of the major traditional conceptualizations of SLTE and lost its prominence due to a number of shortcomings.Behaviourism views learning as imitations of a model of a target behaviour which is broken down into sub-behaviours (Roberts, 1998).Model-based teacher education is associated with the craft model of language teaching (Wallace, 1991).From this perspective, the knowledge base of SLTE is a system of discrete model behaviours or skills presented by an experienced master teacher.Student teachers observe and imitate these models and get feedback from the master teacher to reinforce their behaviours.The merits of behaviourism as an approach to SLTE is questionable because the language teacher learning process is limitedly viewed as imitation of a set or behaviours and SLTE as prescriptive and oversimplified.It fails to recognise the multidimensional nature of SLTE.According to Roberts (1998), imitation as a learning process neglects appropriate use of behaviours in different settings, prevent creativity, planning and self-evaluation, ignores student teachers' individual differences, and may become inappropriate once the goals of language teaching and LTE change.
Humanistic theory of learning came to be seen as addressing some of the above shortcomings of behaviourism.It emphasizes the role of learner autonomy and individual needs in the learning process.The influence of the values of this theory in the field of SLTE has been mixed.In his critique of humanistic theory in SLTE, Roberts (1998) commented that the theory promotes in-service teacher self-help groups and provides a good framework for teacher self-directed learning.It stresses the importance of taking into account what student teachers bring to the process of learning to teach.However, humanistic perspectives overemphasize inner resources and neglect the social aspects and cross-cultural settings of teacher learning.Roberts (1998) suggested that SLTE needs to take into account both the personal and social aspects of teacher learning.It is also important to consider how the personal and social aspects of teacher learning interface in shaping teacher learning.
Another major traditional conceptualization of SLTE is positivism, which also has drawbacks and is no longer a favourable approach to SLTE.Positivism views knowledge as objective and identifiable and "can be captured through the use of scientific methods" or "careful, systematic processes of data collection, analysis and interpretation" (Johnson, 2009, p. 7).Positivist educational research has focused on good teaching and what effective teachers do.The positivist perspective is in line with Wallace's (1991) applied science model, Freeman's (1996) cognitive view, andFreeman andRichards' (1993) scientifically based conceptions of language teaching.Following this approach, SLTE draws on knowledge about patterns of effective teaching and considers this knowledge as transmittable to teachers from others and from one setting to another.According to Johnson (2009), one of the most vocal criticisms is "the oversimplified, depersonalized, and decontextualized nature of the underlying assumptions of this research" and its negligence of "the complex social, historical, cultural, economic, and political dimensions that permeate schools and schooling in the broader social milieu" (p.8).Drawing on positivist research as its knowledge base, SLTE assumes teacher education settings to be generalizable and considers knowledge as transferable from one context to another.In Johnson's (2009) sense, the most "damaging critique" (p.8) towards a positivist view on SLTE is that it has very little influence on improvement of classroom language teaching and learning.
While both behaviourism and positivism emphasize the role of applying model behaviours in SLTE, they appear to fail to recognise that SLTE is a complex multidimensional process and that personal and contextual influences interplay and shape this process.Humanistic theory, despite its central focus on the role of learner autonomy and learning needs, also falls short of the consideration of the array of other influential forces within the personal and contextual spheres and how these interact.The limitations in the traditional ways of conceptualizing SLTE point to the need for the field to have a broader theoretical framework that can capture these complexities.As a result, the field has seen a major re-conceptualization over the past two decades, which the paper now turns to.

A Shift towards a Social Constructivist Perspective
The review of the three major traditional conceptualizations of SLTE above reveals that none of them adequately accounts for the complex nature of SLTE.Therefore, the field has been seeking an epistemology that can address the need for a more comprehensive understanding of teacher learning.A major epistemological shift in SLTE in response to this issue is towards a social constructivist perspective (Crandall, 2000).Constructivism is grounded in the assumption that knowledge is socially constructed and has its origin in the social practices and contexts in which people participate (Brandt, 2006;Chiang, 2008;Crandall, 2000;Johnson, 2006Johnson, , 2009)).In his explanation of constructivist theory, Roberts (1998) argues that "each person's development occurs in constant exchange with their social circumstances: their immediate working relationships, the climate of the school and the wider social forces that affect it" (p.44).
The constructivist perspective on SLTE as such has the capacity to address the shortcomings of behaviourism, humanistic theory, and positivism previously discussed.According to Freeman and Johnson (1998), research in mainstream education has contributed to the shift away from a behaviourist view of SLTE as the field has come to understand that: teachers are not empty vessels waiting to be filled with theoretical and pedagogical skills; they are individuals who enter teacher education programs with prior experiences, personal values, and beliefs that inform their knowledge about teaching and shape what they do in their classrooms.(p.401) Freeman and Johnson (1998) further argued that learning to teach is not merely the accumulation of research outcomes-a view held by advocates of positivism, or scientifically based SLTE.Rather, it is "a long-term, complex, developmental process that operates through participation in the social practices and contexts associated with learning and teaching" (Freeman & Johnson, 1998, p. 402; see also Johnson, 2009;Johnson & Golombek, 2011).Research on SLTE driven by a constructivist perspective seeks to uncover "how teachers participate in and constitute their professional worlds" (Johnson, 2009, p. 9).Emphasizing the important role of the sociocultural aspects of teacher learning, the constructivist view also overcomes the overemphasis on inner resources of the humanistic view on SLTE.This epistemological shift towards constructivism entails a methodological change in SLTE research from merely descriptive, observational studies towards descriptions and explanations of teachers' practices.Within a constructivist paradigm, the personal and contextual aspects of teacher practices have powerful roles in shaping the ways teachers work, and therefore are instrumental in the understanding of teacher practices.For example, a study on a preservice teacher's school-based practicum experience (M.H. Nguyen, 2014) shows that the preservice teacher experienced strong emotions that in turn influenced her professional learning experience.These emotions resulted from the interaction between a multitude of factors such as the contradictions between her mentor teacher's view of teaching and that of her own or between her learning needs and the level of support  (Yates & Muchisky, 2003, p. 140).They argued for the relevance of SLA research in SLTE and added that it is language teacher educators' job to "articulate" (p.140) how to apply SLA research to language teaching pedagogy.Yates and Muchisky (2003) seem to ground their argument in the positivist perspective on SLTE discussed above, which is in line with Wallace's (1991) applied science model, Freeman's (1996) cognitive view, and Freeman and Richards' (1993) scientifically based conceptions of language teaching.In a response to Yates and Muchisky (2003), however, Freeman and Johnson (2004) attributed the critique to a confusion "between what teachers need to know to teach language and what teacher educators need to know to prepare those teachers to teach language" (p.120) and emphasized that their proposed knowledge base is not one of language teaching, but one of SLTE.
An analysis of Freeman and Johnson's (1998) framework shows that it does indicate coverage of knowledge from SLA, although this knowledge, together with many other related disciplines, is not visible in this framework.If the framework is considered as "a broader epistemological framework" (Freeman & Johnson, 1998, p. 405) that helps "to shape a general research agenda that can elucidate the knowledge-base of [SLTE]" (Freeman & Johnson, 1998, p. 407), knowledge from SLA can fit into the first category -the teacher as learner of teaching.Evidently, various studies have found that teachers bring to practice prior knowledge, beliefs and experiences, which interplay with other factors in shaping teacher practice (e.g., Atay, 2007;Macalister, 2012;Mak, 2011).Knowledge about SLA, including knowledge about the worlds language learners bring in that influence their own language learning experience, can well be in this domain and interface with the learner-teachers' worlds, both of which are immersed with the societal milieu in shaping teacher learning.
Secondly, Tarone and Allwright (2005) raised another concern that Freeman and Johnson's (1998) framework does not account for a clear role for the language learner.They described this lack of a clear understanding of the learner as "very troubling" (p.18).Tarone and Allwright (2005) further added that the knowledge base of SLTE in their view should include a clear understanding of learners with regard to who they are, why they learn, what they learn, and so on, and how teachers negotiate the activity of teaching and learning with them.In their response to the critique above, although Freeman and Johnson (2005) briefly said that they never rejected the role of the learner, they did not provide a clearer idea of how this aspect fits into their framework for the knowledge base of SLTE.Freeman and Johnson (2005) only acknowledged the role of the learner by borrowing from Tarone and Allwright (2005) that " [teaching] is not an activity one does by oneself" (p.18).The present paper argues that the role of the learner can be viewed as part of the context aspect of Freeman and Johnson's (1998) framework.This is supported by an activity theory perspective (e.g., Engeström, 1987Engeström, , 2001;;Leffa, 2005) in that there are people in the context of language teaching who co-participate in the teaching activity as members of community, among whom learners are the most obvious.This is empirically evident in a growing body of research where language learners were found to play an influential role in shaping the preservice teacher's professional learning experience (e.g., de Courcy, 2011;Gao & Benson, 2012;M. H. Nguyen, 2014;Riesky, 2013).
Therefore, despite the criticisms, Freeman and Johnson's (1998) proposal presents a useful broad framework that accounts for the teacher-learner, the context, and the activity of teaching and learning.It corresponds to the emerging sociocultural approach to SLTE research, which considers the interplay between these three aspects as instrumental in understanding teacher learning.This paper would, however, argue that the sociocultural contexts of teacher learning are not limited to school settings as proposed by Freeman and Johnson (1998).Rather, the contexts expand beyond schools to encompass the broader societal milieu such as tertiary (e.g., teacher education courses), state and national (e.g., curricula and policies), and global contexts (e.g., knowledge flow, English as an international language), with one embedded in another.

Contemporary Research on L2 Teacher Learning in Light of the Re-Conceptualization of SLTE
In accordance with the shift towards a social constructivist perspective and the re-conceptualized knowledge base in SLTE, there is a substantial body of scholarship on L2 teacher cognition (for comprehensive compilation and examination of this research literature, see Borg, 2003Borg, , 2006)).This body of research focuses on understanding "what teachers think, know, and believe, and how these relate to what teachers do" (Borg, 2011, p. 218).Commenting on the contribution of this research literature to the field, Johnson (2006) wrote, "many factors have advanced the field's understanding of L2 teachers' work, but none is more important than the emergence of a substantial body of research now referred to as teacher cognition" (p.235).This body of studies offers insights into "the complexities of who teachers are, what they know and believe, how they learn to teach, and how they carry out their work in diverse contexts throughout their careers" (Johnson, 2009, p. 10).It has established that teachers' prior experience, knowledge, beliefs, interpretations of their practices, and, most importantly, the sociocultural contexts of their practices are "extremely influential" (Johnson, 2006, p. 236) in shaping and explaining the ways teachers do their work (Borg, 2003(Borg, , 2005(Borg, , 2006(Borg, , 2009(Borg, , 2010(Borg, , 2011;;Johnson, 2006Johnson, , 2009)).For these reasons, this body of research is now essential to the sociocultural perspective on SLTE (Johnson, 2009), which is discussed in the section that follows.
Regarding personal influences, there have now been studies that seek to understand teachers' professional learning in relation to what they bring into the learning process.However, there remains a lack of a comprehensive view of the teacher as a learner of teaching.Despite commonly studying teachers' professional learning, a number of studies look into their cultural backgrounds (e.g., Gan, 2013;Gao & Benson, 2012;Miller, 2007;Nemtchinova, 2005), while others investigate prior beliefs (e.g., Le, 2014;Mak, 2011;Ng, Nicholas, & Williams, 2010;Tang, Lee, & Chun, 2012;Yuan & Lee, 2014), emotions (e.g., Atay, 2007;Benson, 2012;Brandt, 2006;Farrell, 2008;H. T. M. Nguyen, 2010;Pillen, Beijaard, & den Brok, 2013;Trent, 2013), and professional identity (e.g., Haniford, 2010;Miller, 2007;Trent, 2011Trent, , 2013)).Although various personal factors have been accumulatively accounted for in the literature, it seems to be challenging to try and aggregate or compare findings from these studies due to their different focuses and scopes and a lack of a broad framework that allows for research to account for teachers' personal influences more comprehensively and systematically.
There is another trend of research that acknowledges the importance of the sociocultural context, which extends the body of research on personal influences mentioned above.For instant, a number of studies consider the different groups of community members involved in SLTE that influence the learning process, such as university academics (e.g., Gan, 2014;H. T. M. Nguyen, 2010), school mentors (e.g., Atay, 2007;Brandt, 2006;Farrell, 2008;Gan, 2014;Gao & Benson, 2012;H. T. M. Nguyen, 2010;Riesky, 2013;Trent, 2011Trent, , 2013;;Urzúa & Vásquez, 2008;Yuan & Lee, 2014), other teachers-learners (e.g., Dang, 2013;Gao & Benson, 2012; H. T. M. Nguyen, 2013; H. T. M. Nguyen & Baldauf, 2010; H. T. M. Nguyen & Hudson, 2012), and language learners (e.g., de Courcy, 2011;Gao & Benson, 2012;Yuan & Lee, 2014).Some researchers have looked into the rules and policies regulating language teaching and learning and SLTE in specific contexts (e.g., Atay, 2007;Cross, 2006;Cross, 2010;Gao & Benson, 2012).The role of tools and artefacts in mediating teacher learning is also an emerging theme in research on SLTE (de Courcy, 2011;Johnson & Dellagnelo, 2013).The context of SLTE is complex and involves multiple factors.These factors not only interact with what the teachers bring in and their learning activity, but also interplay with each other in shaping the way teachers learn to teach.The studies mentioned above offer valuable insights into different aspects of the context and how they influence teachers' professional learning.However, each of them tends to focus on certain aspects of the context and neglect others.It is at this point that the urges for broader, coherent conceptual framework to organise our current understanding of teachers' thinking, knowing, and doing that has been put forth at the beginning of this paper becomes highly relevant and timely.
Perhaps the highlight of the past decade has been the emergence of some studies that take into account the complex, multidimensional context of L2 teacher learning.From a sociocultural perspective, Ahn (2011) analyses "the various individual, social, and sociocultural factors" (p.240) present in the context and how they influence preservice teachers' practicum experience within the context.The study reveals a range of contextual factors shaping the preservice teaching experience, such as classroom rules and an expansive community that includes pupils, mentors, peers, parents, and university professors.Using activity theory as an analytical framework, the study sheds light on the contradictions between contextual factors and how the contradictions shaped the preservice teacher's instructional activity.Also from a sociocultural perspective, several studies by Dang and colleagues (Dang, 2012(Dang, , 2013;;Dang & Marginson, 2013;Dang, Nguyen, & Le, 2013) explore preservice EFL teachers' university-based practicum experience in Vietnam.The studies examine the influence of context at local, institutional, national, and global levels on preservice teachers' professional learning during a paired placement.Factors such as border-crossing of people and organisations, rich source of internet ELT materials, availability of internet technological tools, a world-shared culture, the spreading of English as a means of instruction, global knowledge flows, and national language policies are among the most important contextual factors that influence the paired placement experience of the Vietnamese preservice ELT teachers.Also taking a sociocultural approach, M. H. Nguyen (2014) is able to trace the influence of multiple personal and contextual factors on a preservice English language teacher's learning, including a non-native English speaker background, inadequacies in English language, power relations within the teacher learning context, rule systems, and mentoring support.Especially, the study with the support of a sociocultural framework is able to systematically analyse the interaction between these factors and identify contradictions between them and how the contradictions contributed to the teacher's emotional experiences.In general, supported by a sociocultural framework, the studies by Ahn (2011), Dang and colleagues (Dang, 2012(Dang, , 2013;;Dang & Marginson, 2013;Dang et al., 2013), and M. H. Nguyen (2014) demonstrate a more comprehensive understanding of the SLTE experience in relation to the complexities of personal and contextual factors.

The Potential of a Sociocultural Perspective in Researching L2 Teacher Learning
With the influence of the epistemological shift towards social constructivist theory of language teacher learning, the reconceptualized knowledge base of SLTE, and the relevant body of scholarship on language teacher cognition, a sociocultural perspective on SLTE has become "a way of conceptualizing teacher learning that informs how teacher educators understand and support the professional development of L2 teachers" (Johnson, 2009, p. 16) and continues to be influential in the field.From a sociocultural perspective, teacher learning is socially constructed, resulting from participating in sociocultural activities and contexts of teaching, and emerging from constructing and reconstructing existing knowledge, beliefs and practices rather than transmitting theories, methods, or materials to teachers (Golombek, 2011;Johnson & Golombek, 2003, 2011;Singh & Richards, 2006;Waters, 2005).Johnson (2009) summarized several key tenets of a sociocultural perspective on SLTE.Firstly, a sociocultural perspective on SLTE views teachers as the learners of teaching and focuses on L2 teachers' professional development.Therefore, L2 teachers are considered the centre of learning to teach, and what they bring with them to the professional learning process and how they function during this process is of prime importance.Secondly, a sociocultural perspective on SLTE conceptualizes teacher learning as a sociocultural activity situated in sociocultural contexts and mediated by artefacts.It pays great attention to the sociocultural contexts and processes in which teacher learning takes place.It treats the context of teacher learning as a crucial component of teachers' learning as the context interacts with the person of the teacher in shaping their learning experience.Moreover, this perspective also highlights the influential role of existing and potential mediating tools in L2 teacher professional learning.Within the sociocultural framework, genetic method (Vygotsky, 1978) and activity theory (Engeström, 1987(Engeström, , 2001) ) appear to be two useful concepts that have potential to support research in SLTE in addressing the shortcomings of the current body of research discussed above.
Genetic method, which demands the central role of historicity in the overall methodological and analytical design of research into everyday human behaviour (Vygotsky, 1978(Vygotsky, , 1981)), supports an explanatory approach to research that goes beyond simply describing immediate aspects of the present form of human activity.In other words, "it seeks to explain the situation by tracing its origins and evolution" (Engeström & Sannino, 2010, p. 7).According to Vygotsky, "mere description does not reveal the actual causal-dynamic relations that underlie phenomena" (1978, p. 62), and "everyday human behaviour can be understood only by disclosing the presence of four general fundamental genetic stages through which behavioural development passes" (1981, p. 156).Vygotsky's genetic method involves four genetic domains, namely phylogenesis, sociocultural history, ontogenesis, and microgenesis, corresponding to four levels of analysis according to their relationship with physical time.Although Vygotsky conducted most of his empirical research on higher metal functioning in the ontogenetic domain, he argued that the only way to understand ontogenesis properly is to put it in a larger, integrated picture involving the other genetic domains (Wertsch, 1985).Cross (2010) explained the genetic domains as follows: [T]he phylogenetic domain concerns the development of humankind as a natural species (i.e., physical evolution), the cultural-historic focuses on development in terms of the broader "external" world within which humans exist (i.e., the social, cultural, and historic basis for development), and ontogenesis shifts the focus to development of the individual subject across the human life span.This, itself, is the culmination of microgenetic development-the momentary instances of concrete, practical activity that subjects engage in with the world around them.(pp.438-439; original emphasis) Sociocultural research in social sciences in general and education in particular has mostly focused on the microgenetic, ontogenetic, and cultural-historic domains.The fourth domain, phylogenetic domain, which is concerned with the physical evolution of mankind as a species, is largely the focus on bio-anthropology, and therefore not considered in social sciences including SLTE.
The second concept, activity theory (Engeström, 1987(Engeström, , 2001)), is an evolving analytical lens to conceptualize the sociocultural context of human activity and how it shapes such activity.The current form of activity theory is the third generation (Engeström, 2001), which seeks "to understand dialogue, multiple perspectives, and networks of interacting activity systems" (p.135).This analytical tool responds to the need for a broad, unifying theory to underpin research in SLTE argued for at the beginning of this paper.It takes into account the personal worlds that teachers bring to the learning activity, and the systemic relationships between these and the learning objectives, the cultural tools mediating the learning process, the rules and policies regulating teaching and learning, the community of people involved, and the responsibilities held by different people in the communities.
The combination of genetic method and activity theory as a theoretical framework requires teacher learning to be analysed in relation to its origins and the inner systemic interactions between its multiple aspects rather than simply describing the current, observable state of the experience.Specifically, it requires an understanding of the teachers' day-to-day professional learning experiences (i.e., microgenetic domain) on the basis of an understanding of their genetic antecedents and the inner relations between aspects of the learning activity.The genetic antecedents include the participants' personal backgrounds and relevant prior experiences (i.e., ontogenetic domain) and the broader social, cultural, political, and historic context (i.e., cultural-historic domain) from which the professional learning experience has emerged.The inner systemic relations exist between different aspects of the learning activity, including links across the genetic domains.This analytical approach is instrumental in the explanation of why teachers do what they do in their teaching context (Johnson, 2009), and essentially addresses the need for a unifying conceptualization of SLTE argued for elsewhere in this paper.

Concluding Remarks
The present paper reviewed the literature on the major conceptualizations of SLTE in relation to the key conceptualizations of language teaching.The review revealed shortcomings in traditional perspectives on SLTE and the need to re-conceptualize SLTE.It then reviewed the recent re-conceptualization of SLTE with a focus on the shift towards a social constructivist perspective, a redefinition of the knowledge base of the field, a sociocultural perspective on SLTE, and how the recent body of research has responded to the shift towards a sociocultural perspective in SLTE.
The survey of the SLTE research literature shows that as a field, SLTE has studies that accumulatively examine all the three aspects of teacher learning from a sociocultural perspective as proposed by Freeman and Johnson (1998), including the context, the teacher as learner of teaching, and the activity of teaching and learning (Figure 1).However, there remain some major gaps in this body of literature.First, individual studies tend to focus on one or a few issues under the three broad aspects.As a result, it is challenging to aggregate comprehensive insights into SLTE based on the current literature.Second, what is problematic is that the body of scholarship falls short of a consistent conceptualization of 'context'.This lack of theorisation is one of the reasons why there is inconsistency between studies in terms of what constitutes the context.While some researchers consider the context as the community involved in the teaching and learning activity (e.g., Atay, 2007;Brandt, 2006;de Courcy, 2011;Gan, 2013;Trent, 2013;Urzúa & Vásquez, 2008;Yuan & Lee, 2014), others account for the systems of rules (Atay, 2007;Engin, 2014;Gao & Benson, 2012) and pedagogical tools (de Courcy, 2011;Johnson & Dellagnelo, 2013).As what constitutes context of teaching and learning varies from one study to another, it is really challenging to synthesise and compare findings from different studies.It is argued that there needs to be a coherent conceptualization of 'context' that "brings together the disparate threads of research" in SLTE (Cross, 2010, p. 437).Such a conceptualization needs to be broad enough to account for the multidimensional and complex nature of context of L2 teaching and learning.For the field to address these gaps and move forward, this paper calls for more research using a sociocultural framework to approach SLTE more comprehensively and systematically.
Drawing on the literature, this paper identified that a sociocultural perspective has become a powerful way of understanding L2 teacher learning.Within a sociocultural framework, two particularly useful concepts include genetic method (Vygotsky, 1978(Vygotsky, , 1981) ) and activity theory (Engeström, 1987(Engeström, , 2001)), the combination of which empowers research that not only describes how L2 teachers learn to teach but also explains why they act the way they do (Johnson, 2009) by considering personal and contextual dimensions in relation to teacher learning.This perspective on SLTE responds well to the calls for a unifying theoretical framework to understand SLTE that are raised at the beginning of the paper (Barkhuizen & Borg, 2010;Borg, 2006;Borko et al., 2007;Burton, 1998;Johnson & Golombek, 2003).The field has begun to embrace this theoretical orientation in its efforts to gain more comprehensive and in-depth understanding of L2 teacher learning, but studies have only appeared periodically.Such research has potential to offer systematic implications for improving the quality of SLTE, so more research on L2 teacher learning using a sociocultural framework would contribute to advancing the field.