On the need of pluralism and common ground in SLA

Science, like the Mississippi, begins in a tiny rivulet in the distant forest. Gradually other streams swell its volume. And the roaring river that bursts the dikes is formed from countless sources. (Flexner, 1939, p. 547) Hyperbolic claims that SLA is in crisis (!), that a unifying theory is overdue, or that research must be oriented toward pedagogy have resurfaced once again—most recently in the response by Lantolf et al. (2025) to the Special Issue on Synergies in Second Language Acquisition and Teaching (SLA/T) (Atkinson et al., 2025). Our own position is diametrically opposed to such claims. We view SLA/T as a vibrant and evolving field that has made substantial progress. The simplistic dichotomies between cognition and social action that characterized earlier decades have been questioned, softened, and, in many cases, transcended. We live in an era of team science that routinely interfacses multiple perspectives, methodologies, and theories. Acknowledging the multifacetedness of our objects of study makes it relevant to draw upon a plurality of approaches while working toward the same goal: a more robust understanding of what it means to learn a second language. It is a sign of the maturity of our field that cross-fertilization among diverse approaches and methodologies has intensified, and perhaps most importantly, antagonistic stances have given way to mutual respect and recognition of the value of difference. The increasing number of initiatives that seek to integrate perspectives (the Synergies Special Issue, Atkinson et al., 2025; the Special Issue on Emergent L2 Grammars in and for Social Interaction, Eskildsen and more recently Hammond, 2025, seeking to bridge Universal Grammar with usage-based accounts; for earlier calls see, e.g., Douglas Fir Group, 2016; Hulstijn et al., 2014) testify clearly to the fact that the field is “on the move.” These efforts bring us closer to grasping the immense complexity of second language acquisition (SLA). Far from being in crisis, the field is flourishing. We see the current moment as fertile terrain for continued advancement—provided that researchers actively cultivate common ground while upholding the value of pluralism within SLA/T. Scientific progress is incremental and unpredictable. It often arises from chance empirical discoveries and advances step by step, fruitfully building on cumulative and dialogic confrontations of perspectives and procedures. This has been beautifully captured by Abraham Flexner, cited above, in his reflections on the importance of science. SLA is inherently multifaceted. No single overarching theory or method can adequately account for its complexity, nor definitively predict L2 speakers’ learning trajectories. Multiple research perspectives help to illuminate different aspects of language as an essential condition of the human experience. There is no ONE theory that accounts for all aspects of second language development. Bridging research and practice is intricate. Given that classroom practice is complex, dynamic, and multifaceted, a full range of research–pedagogy praxis is needed to interpolate insights that span from statistical modeling techniques and lab-based experimental studies to thick description and qualitative observations of classroom-based practice. Different forms of SLA research serve different purposes. For example—and to simplify—use-inspired, practice-driven inquiry represents one type; curiosity-driven, basic research represents another. The latter's value for practice is often unpredictable and should not be constrained by immediate pedagogical needs. All authors in the MLJ Synergies Special Issue utilize one or more named theories, approaches, and methodologies. Our individual/team perspective statements described these commitments. Although historically situated, theory and method are likewise emergent in their application to novel data and situations, and therefore must accommodate newly arising observations and empirical evidence. Accordingly, we take up Pennycook's (2018) notion of assemblage as a productive way to conceptualize inquiry in applied linguistics, one that promotes reflexive research orientations while guarding against the epistemic narrowing produced by prescriptivist appeals to disciplinary unity, which we contend characterizes Lantolf et al.’s commentary. Doctrinal commitments to theory and method have their place. Doctrinal commitments to theory and method can also overdetermine the object of analysis and eliminate opportunities for new discoveries. The Synergies Special Issue was fundamentally cooperative and inclusive in its intent, asking: What might we learn from and with one another if we tried to forge connections across the ontological and epistemological chasms that separate us? A few examples from our own research are briefly described below. Within applied linguistics, sociomaterialist and posthumanist approaches (Guerrettaz et al., 2021; Pennycook, 2018) have encouraged scholars to conceptualize language learning as an emergent, distributed accomplishment arising within assemblages of bodies, artifacts, spaces, and histories. Conversation analysis (CA), meanwhile, offers a micro-analytic account of how human action, including learning, is organized and accomplished in turn-by-turn interaction, and contemporary research increasingly demonstrates that the body, material artifacts, and spatial arrangements are integral to action formation and sequence organization (Goodwin, 2013; Hellermann Piirainen-Marsh, Lilja, Sert Thorne et al., 2021). Ongoing questions about the commensurability of CA and sociomaterial approaches offer opportunities for continuing engagement, debate, and theoretical development. The combination of usage-based linguistics (UBL) and CA in SLA, developed by Eskildsen (2011), emerged from a confrontational research process that exposed limitations in existing theoretical frameworks. Initially grounded in usage-based models of language, the research encountered two major problems: one empirical and one epistemological. Empirically, the phenomenon under investigation—the role of formulaic language in L2 learning—proved difficult to capture in the chosen audiovisual database of L2 classroom interaction from an English as a second language (ESL) classroom in Portland, Oregon. The linguistic productions of L2 learners could not be classified a priori as either formulaic or syntactically creative, rendering this binary distinction empirically untenable. Instead, the data revealed an abundance of recycled language, prompting a shift in focus toward how constructions emerge in L2 acquisition. This shift drew on emergentism, exemplar-based theories of learning, and dynamic systems theory. While subsequent analyses demonstrated that individual cases of L2 learning could be described as exemplar based and frequency gated, these findings appeared epiphenomenal. Usage-based frameworks alone were not sufficiently attuned to the realities of language emergence in interaction and thus could not fully analyze or explain situated L2 development. To address this limitation, conversation analysis was introduced as a framework for understanding social interaction and the situated specifics of L2 construction emergence. CA provided the analytical tools needed to account for how language use unfolds moment by moment in interaction. The resulting integration of UBL and CA—born of epistemological confrontation and synergetic collaboration—has become increasingly established as a distinct and productive approach to L2 research, in dialogue with scholars from multiple disciplines (e.g., Pekarek Doehler and more generally the papers in Eskildsen Thorne et al., 2021) has had unforeseen and significant implications for practice as a result of collaborations with school leaders, willing and interested practitioners, and civil servants close to policy makers. Similarly, theoretical concepts of complex dynamic systems theory (Verspoor et al., 2011), dynamic-usage-based pedagogy (Rousse-Malpat et al., 2019), and basic research into cognitive processes underlying learning vocabulary from plurilingual audio-visual input (e.g., Pattemore et al., 2025) has informed the pedagogical approach implemented in language education at the University of Groningen, that heavily draws on film and language integrated learning (FLIL, Kassenberg et al., 2020)—a methodology that broadly aligns with learning in the wild. Another example is the combination of classroom observations and idiodynamic approaches to study motivation and willingness to communicate within the Complex Dynamic Sytem Theory (CDST) framework (Sulis et al., 2020). Together with other examples of fruitful teacher–researcher collaborations provided in Sato et al. (2025), this shows how a commensurable and synergistic approach to SLA/T can inform teaching and learning practice. Our—and more generally The Synergist's—continuing goal with the Special Issue, then, is to demonstrate the value of fostering common ground. It was, in fact, the explicit aim of the Special Issue editorial team to remind authors to seek out and to document synergies—what we might agree on. One could, of course, have begun from the opposite pole—by emphasizing differences and potential incommensurabilities. Indeed, this possibility was discussed among the Special Issue authors at various points in the development of this collaborative project. Yet experience shows that starting from differences often leads to endless conceptual debates with limited practical payoff. Confronting theoretical and methodological distinctions is of course necessary, but might it not be equally worthwhile to start from convergences? By identifying shared ground, we can cultivate mutual respect among approaches, deepen our understanding of genuine differences, and explore how diverse perspectives might complement and strengthen one another—or even strengthen our own viewpoints, as findings and insights from other paradigms add to our own work. This was precisely the intention of the Special Issue. Each contributor can be held accountable for the processes and procedures for convergence of their perspective on SLA with those of the other contributors, but as a group we do not have a single unified framework. What we have are the synergies that ensued from the convergence efforts. Additionally, the process of working and learning together, which necessitated bridging our differences with humility, was itself valuable and unique. As contributors, we engaged in constructive dialogue with scholars of diverse orientations, emerging from the process with a renewed appreciation for other conceptual frameworks, methods, and findings. Through this exchange, we forged common ground that reaffirms our conviction: pluralism is not a problem to be solved but a condition to be valued if we are to capture the multifaceted nature of SLA. All authors contributed substantially to the design and writing of this commentary. In addition, Simona Pekarek Doehler was responsible for the initial conceptualization and drafting of the general rationale and Steven L. Thorne did the final critical reviewing of the text. Open access publishing facilitated by Universite de Neuchatel, as part of the Wiley - Universite de Neuchatel agreement via the Consortium Of Swiss Academic Libraries. The authors declare that they have no conflict of interest. This commentary does not use any data.