They have been at a great feast of languages, and stolen the scraps.

William Shakespeare, Love's Labour's Lost, Act V, Scene 1

Imagine this: It is 1980 (or 1890, or 1090, or 980, or 109 CE), and you live anywhere on Earth. You've decided that your fortune lies in leaving your homeland to live in another country or empire, working as an immigrant, or a trader, or perhaps as an envoy from your own country, and you see that your success in this endeavor will depend largely on your ability to function well in the language(s) of the country you are moving to. What are your options for learning that new language, in your time? Perhaps you can find some books, or perhaps there are classes you can take, or if you have the means, you'll hire a tutor or find someone who speaks the new language and befriend them. Maybe, if it's 1980, you can find some audiotapes or phonograph records to listen to and imitate. It will be hard, hard work; but you can do it, if you persist: You can learn a foreign language on your own, if there are resources, and if you have the means to obtain them.

But now, it's 1995, and you live in a country with access to a new form of communication, satellite television, which can send you programming 24 hours a day in the language you want to learn – with subtitles (or if you're lucky, captions in the target language). Then, it's 2005, and there are new technologies, personal computers and mobile devices and the internet, and you now have access to vast written and audio resources in the language of your desire, and even, through chatrooms and the new massive multiplayer online role‐playing games (MMORPGs), to live contact with others in their language. It may also be that through a very affordable travel program, you can fly to a country where the language is spoken widely and spend some time there “picking it up” from local people; or perhaps those speakers have come to your homeland and you have a chance to meet with them; or, perhaps you have family or friends in that country you can visit or chat with online. Finally, it's 2015 and then 2020. Advances in access and speed on smarter and smarter phones, tablets, and laptops provide an almost limitless array of sources of the language of your dreams, spoken and written by people who “speak your language” metaphorically as well as linguistically across written, audio, and video platforms. Through constant exposure and a bit of effort, you absorb and then understand and finally, in fits and starts, speak and read and write a new language, if not effortlessly, then with an ease and grace that surprises even you.

What an incredible time ours is for language learning! In the space of a generation – 25 years – all of humanity, or at least that huge part of it with some access to digital communications and/or intercontinental transport, has moved from near‐total dependence on the knowledge and expertise and planning of others to a level of autonomy and opportunity for self‐teaching and “picking up” new languages unimagined in any other period of human history. If you don't believe this or think it's an exaggeration, do this: Go to your local university and seek out some students who are international or “foreign.” Ask them how they learned to speak, read, and write your language so well. Their first answer might be that they took lessons or learned in school. But then, press them: How did they really learn the language? How did they pick up its slang and master its pronunciation so well? How did they acquire its pragmatics, or understanding of use in context? They might hesitate, but in most cases, they will tell you: They learned these things from watching movies online or on satellite television, or from playing video games, or from chatrooms or perhaps from a friend or relative with whom they practiced. Yes, they had a teacher and took classes, but the learning that led to being able to use the language to do things was informal, and came from human contact online or in person, and from watching many, many movies and television shows or listening to a lot of music in their target language.

This may not be the case everywhere, even when and where such opportunities are present. From where I write in the United States, most people remain convinced that languages are among the most difficult (and boring) school subjects. This is true also for countries like Japan or Korea or even southern Europe. But for a growing number of individuals in other places like Morocco or China, where learning English has become a national preoccupation, informal learning has become predominant, even if formal educational systems do not recognize this and if the learners themselves do not always realize the extent to which their learning of English has come if not accidentally then often incidentally from seeking the pleasures of entertainment or human exchange.

What, then, of the formal ways of learning languages – of textbooks and courses of study and sophisticated classroom curriculums that attempt to “naturalize” and make language education as authentic as possible within an official, formal education context? Are these going away, or will they be replaced by informal or perhaps nonformal (e.g. Rosetta Stone; Babbel) modes of learning? The practical answer to this question is likely to be highly dependent on differences in culture and national policy in any locale. Some related but more theoretical and intriguing questions, however, could be: How can or should formal language education take the new opportunities for informal learning into account? Is there a way for formal instruction to integrate or incorporate insights from informal language learning, or are the two as alien and difficult to mix as oil and water? Or does informal learning threaten the continued existence, in the end, of formal instruction to an extent that it needs to be ignored or denied or even resisted by educators? This final possibility leads to one last question: What is the future of language education itself? What will become of learning, whether formal, nonformal, or informal; of teaching itself; and of the design of curriculum, especially in an age of increasingly sophisticated forms of Artificial Intelligence (AI) and increasingly ubiquitous access to digital streaming, cyber and cyborg technologies, and future technologies yet to be imagined or named?

A new field of research

This Handbook represents our collective best attempt as chapter authors to organize research and theory on informal language learning around a set of subtopics, and to lay the groundwork for a new and very vibrant subfield within applied linguistics. This is an ambitious goal, and, it must be acknowledged, one that is not without antecedents. As far back as the 1970s, Krashen (1976) and d'Anglejan (1978) reported on (and advocated for) the role of informal experiences in “adult” (i.e. second) language acquisition and learning, followed by Ellis (1980, 1982) in the early 1980s. And nearly every foreign language teacher we have ever known would agree that in areas such as acquiring pronunciation and fluency, there is no substitute for “immersion” in a community of speakers. But in these cases, a distinction between acquisition, or the “picking up” of language, and learning, or the conscious, organized study of and practice in a second language, has been made, in which very often the center of the learning/acquiring process was a classroom, with activities organized and led or facilitated by a designated teacher.

The authors of this Handbook are focusing on a set of phenomena that differ in some significant ways from earlier days before digital communications and globalization became as pronounced and ubiquitous as today. First, informal language learning today differs from the past in its breadth of opportunities for learning. Whereas 30 years ago authentic informal encounters with another language would need to come through travel, close association with a speaker of that language, or to a more limited extent through foreign movies rented at a video store, by 2003, learners could download music and videos online from iTunes in a wide variety of languages or chat with other players on MMORPGs all over the world or in a variety of chatrooms like MSN. Beginning in 2005, YouTube made it possible for people to see and hear each other speaking extemporaneously all over the world; Facebook (from 2004) and other social networking sites made it easier than ever before for people from Iceland to Tierra del Fuego to share themselves, their culture, and their language in immediate and often very intimate ways; and services like Google Translate (from 2006) made it possible for people to understand each other (or at least short utterances) with greater ease than ever before. Many of the new platforms and media formats were not developed or intended for language learning specifically, but they could be appropriated for that purpose; and then early language learning platforms like Live Mocha (in 2007) appeared, which gave rise to the more elaborate, commercial platforms of today, such as Babbel, Duolingo, and the online version of Rosetta Stone. Finally, and at the same time, increasingly cheap and extensive networks of air travel as well as dramatic increases in migration from South to North created opportunities and needs for acquiring a second, third, or fourth language.

A second difference is that the multiplicity of possibilities for exposure and engagement with other languages also blurs the distinction between acquisition and learning of languages as well as distinctions often made between informal, or incidental, and nonformal, or deliberate but out‐of‐school, learning. If one is learning partly through conscious attention to a language and partly through immersion in the pleasure of a video text, is one acquiring a language or learning it? Consider the example of the teenager in Turkey who becomes “hooked” on K‐pop, picks up some expressions, and then begins consciously to study Korean to understand the lyrics sung by his or her favorite group. Is that learner “acquiring” Korean by picking it up from the music she or he loves, or is that teenager “learning” Korean by studying it? Or, consider the case of the Moroccan university student who learns English by watching TED Talks with captions or subtitles in Arabic or French. Is that student studying (learning) English or acquiring English if she takes notes as she watches, or rewatches some parts of the video that she particularly enjoys, “soaking up” the gestures and expressiveness of the speaker along with vocabulary and ideas? In other words, does the distinction made in earlier times between acquisition and learning or among formal, nonformal, and informal approaches matter for learners anymore; and if it doesn't matter for learners, then should it matter for researchers and, more critically, for educators?

A final difference closely related to the second is that both the ubiquity and diversity of these new opportunities for language learning are also challenging relations between the didactic and the auto‐didactic, or between the curriculum of the classroom and the curriculum of social media, tourism, the workplace, and movies/TV/music – in short, between what used to be considered the unavoidable work of “mastering” another language, and what learners often experience as the joyful play of interacting with others with and through texts, and the sense of reward and mastery of language that comes from using a new language in highly communicative but often grammatically imprecise ways.

Plan of the handbook

The plan for this Handbook has been as broad and inclusive as its practices of definition. It begins with reviews of well‐defined areas that are relevant to the conceptualization of informal language learning as a developing field of research; but then it moves to sections that present findings and theoretical perspectives that are interdisciplinary and that explore a diverse range of the media and manifestations of informal language learning. The editorial goal and the goal of chapter authors has not been to define, but rather to do the basic work of establishing a robust new field of research: to describe, to question, and most of all to explore; and only afterward to try to delineate a path forward for theory, for empirical research, and for the educational work of curricular and instructional development.

Let's be candid here: During the initial writing of the chapters, many authors wrote to say they were struggling because they were not finding a great deal of previous research on the informal aspects of language learning/acquisition among adolescents and adults. They said they needed, in many cases, to “start from scratch” and engage in “a lot of conceptualization” that involved generating very basic questions, forming categories, and making distinctions among cases and phenomena that were original to their topic; and, they wanted to know, was that okay?

The response was: Of course; and then, “Go for it.” No one should have been surprised in a field as dominated for years by the assumption that nearly everyone past childhood needed to be taught a new language formally in order to learn it, that there would be very little on cases in which learners were effectively teaching themselves or simply “picking up” a language from their favorite media or combining learning informally with formal language classes. That cases of these latter phenomena are increasingly documented but remain largely ignored within both the applied and “pure” fields of linguistics and other social sciences is not an indication of their irrelevance but of the need for more research and theory in this area, and hence, of the need for the chapters of this Handbook.

Part I: Theorizing Informal Language Learning, offers five chapters, each authored by leading experts, that explore core theoretical issues of informal language learning from the perspective of research on motivation, cognition, multimodality, linguistics, and literacy. In Chapter 1, Alice Chik writes about one of the most vexing topics for language teachers, but for informal learners one of the least problematic: motivation. For Chik, the difference between learners' motivation in the classroom and during informal learning is a function of learners' language identity and sense of themselves as second language learners. She grounds her argument in her ongoing ethnographic study of her own and others' learning practices using the online platform, Duolingo, to explain how the affordances of this platform can motivate language learners both informally and in classroom settings.

In Chapter 2, Kiel Christianson and Sarah‐Elizabeth Deshaies take up another “thorny” issue in language acquisition, the question of how it is that children seem to “pick up” languages with ease whereas adults are far more likely to struggle and never fully master any language they try to learn. Cognitive differences between children and adults seem the most likely source of differences in proficiency in language learning, and to offer some insight into the cognition of informal older learners. Their discussion, however, suggests the opposite of conventional wisdom, that is, that many characteristics of adult learners, such as metalinguistic awareness and the ability to generate explicit learning strategies and seek explicit reinforcement for their learning, would seem to give them a cognitive advantage over children. Why, then, do adults seem to struggle with language learning? Christianson and Deshaies argue that it is often situational factors and other learned behaviors, such as the relative complexity of adult linguistic environments compared to children's and adults' “resistance to production” – i.e. fear of making an embarrassing mistake – that limit adult success. But these are conditions that many informal learning platforms, such as video games and captioned video, would seem to mitigate, suggesting that the conditions of informal learning may provide cognitive scaffolding for learning that more formal conditions do not.

In Chapter 3, Mark Dressman presents a new theory of how multimodality, or the combination of multiple sources of semiotic input, such as spoken and written language or language combined with visual images or music, is a key aspect of informal language learners' success. Dressman rejects prevailing theoretical perspectives, which argue that words and images mean in transposable ways and that it is their redundancy that accounts for multimodality's power. Instead, he builds on the work of C.S. Peirce and linguistic pragmatics to argue that it is the complementarity of multiple sign systems and the reinforcement they provide for the interpretation of messages that create conditions for learning within informal contexts that are superior to the more logocentric approaches of formal instruction.

Chapter 4, by Silvina Montrul, examines the topic of language learning in multiple contexts through a comparison of the environmental constraints, opportunities, and consequent outcomes of three conditions: first language acquisition; second language learning in formal contexts; and heritage language learning, which shares some features of both informal, highly contextualized, and more formal, instructionally based language learning. Montrul's work on heritage‐language learners, or learners who typically acquire their immigrant parents' language informally in childhood but may not acquire full proficiency or literacy in that language until they study it formally later in life, points to the critical importance of context in determining both the quantity and quality of proficiency when a second language is acquired and/or learned informally.

The final chapter in Part I focuses on second language writing and more broadly on literacy within informal contexts. In Chapter 5, Paul Kei Matsuda and Melika Nouri explore the apparent contradictions between literacy, which is typically acquired formally as an extension of first language learning, and informal writing, noting in the chapter's Conclusion that “Because of its low‐stakes nature, informal writing can be a great way to facilitate language and literacy development among younger students and beginning language learners.” This chapter also prefigures the discussion of relations between formal instruction and informal learning in Part V of the Handbook.

Part II: Learning in Digital Contexts, is the first of two Parts that review research on specific means by which informal language learning takes place. The six chapters in this Part review research on learning through media that are necessarily digital and computer‐based. In Chapter 6, Randall William Sadler explores the implications of virtual landscapes such as Second Life for language learning. The three dimensionality (albeit on a two‐dimensional screen) of these digital platforms enables a level of social interaction via avatars, or characters that may (but probably do not) resemble the individuals behind them, provides opportunities for multidimensional social interaction as well. Chapter 7, by Stephanie W.P. Knight, Lindsay Marean, and Julie M. Sykes, explores learning in another 3D virtual space, that of digital gaming and MMORPGs. Through the affordances of high‐speed internet connections, at any given moment thousands to hundreds of thousands of players from all over the world are competing and cooperating with each other to conquer new territories, build new civilizations, or simply “live” to play some more. In the process, many of these players are also learning to communicate with each other, not only in English but any number of languages.

The final sections of Chapter 7 touch on a related form of online language learning, the use of apps such as Babbel and Duolingo. Knight, Marean, and Sykes note that the premises of language acquisition that drive these quasi‐games (i.e. that language acquisition is tantamount to acquiring a grasp of grammar and basic vocabulary and expressions) contradict “best principles” language education, and they are dubious about the success such apps might have in real‐life settings. A more sanguine view of these apps is taken by Panagiotis Arvanitis in Chapter 8, who argues through original research conducted with users of the apps that these apps perform a vital service for some learners which, combined with more spontaneous and fully informal supports, can prove successful.

In Chapter 9, Shannon Sauro reports on learning with a much slower paced and in some ways more traditional approach, that of fan fiction (or FanFiction), in which authors write and publish online sequels, prequels, and spinoffs to their favorite books, movies, and television series. The opportunity for self‐expression within familiar worlds and characters and through the appropriation of vocabulary and idioms picked up from reading or viewing is not only powerfully motivating but highly effective in building learners' confidence in themselves as writers and critical readers of their own and others' work.

Chapter 10, by Tatiana Codreanu and Christelle Combe, focuses on another powerful medium for self‐expression and language acquisition, the vlog, or video blog, which they define as “personal videos posted regularly by users on a specific theme” (see the section “The Social Web”), usually but not exclusively on YouTube. Unlike Sauro, however, their focus is not as much on the producers of these digital texts but on their consumers/readers, who tune in regularly to learn from peers across the world such as BenDeen, a Korean American living in Seoul, or Ouissal Id Hajji, a Moroccan teenager who learned English as a child by watching My Little Pony on satellite TV. Codreanu and Combe point, however, not only to the significance of the vlogs themselves but to the multilingual commentary that runs below them on the YouTube site, as a means and motivation to acquire, both consciously and unconsciously, new language.

Chapter 11 is authored by Agnes Kukulska‐Hulme and Helen Lee. In a comprehensive review of their and others' research on the use of mobile devices in language learning, they explore the multiple ways that mobile devices such as smartphones and tablets can provide a platform for a range of learning opportunities, from the informal and opportunistic to the more formal and deliberate. Of special interest to them are the opportunities for collaborative learning and social contact, both on‐the‐go and in more planned and organized online settings.

Part III: Learning through Media and Live Contact, continues the Handbook's review of some of the most frequent media and resources for available to language learners, but with a less digitally driven focus. In Chapter 12, Robert Vanderplank offers a review and critique of one of the most venerable and frequently used sources of new languages – captioned/subtitled video and movies. Vanderplank notes a critical distinction in the research literature between videos that are subtitled (in which language in the video is translated into a language known by the listener) and those that are captioned (in which the language of the video is represented in its written form in an embedded caption). Although research shows that learning occurs in both cases, captioned videos are typically found to produce more learning. Similarly, in Chapter 13, Karen M. Ludke draws on her own experience as well as recent research to argue that songs and music can play a vital role in acquiring a second language. In fact, and in another chapter that prefigures the chapters on the integration of in‐ and out‐of‐classroom learning, she provides evidence that songs provide a powerful bridge between informal and formal learning.

The remaining four chapters in Part III all focus more on the life histories and situations of specific groups of language learners than on the media or resources of their learning. Chapter 14, by Kristen H. Perry and Annie M. Moses, reviews recent research on the language‐learning strategies of immigrant youth. Compared to past decades, immigrants in the early twenty‐first century are often able to keep in close and immediate contact not only with people in their home countries but with other immigrants across their new countries and around the world. Perry and Moses emphasize the multiplicity of paths and opportunities these youth take in their choice of media for both learning new languages and maintaining their native language. Chapter 15 also focuses on immigrants' language learning, but within the service work sector. Hania Janta and Stefan Keller provide a very comprehensive review and analysis of recent empirical research on how immigrant service employees learn (and companies build on) new languages, and provide a classification system for learners' strategies, which range from high‐intensity learning on the job to low or no interaction and avoidance of communication. In Chapter 16, Jana Roos and Howard Nicholas focus on learning opportunities provided by the “linguistic landscape,” that is, the appearance of non‐native written and spoken language within native‐language contexts on signs, billboards, television commercials, and so on, and how learners use these instances as entry points for exploration. Although learners are unlikely to acquire communicative competence in a language from the landscape alone, the frequent playfulness of the language that is used and its “randomness” can be very appealing to learners and help to make the learning of a language in formal contexts more relevant and engaging. Chapter 17, the final chapter of Part III, by Montserrat Iglesias, examines learning through “language tourism,” or the acquisition of a new language through relatively short (a few weeks; a semester) stays in a country where that language is spoken. Iglesias documents and argues for the ways that even relatively brief encounters within another linguistic space and culture not only develop learners' proficiency in a new language but also their linguistic identities and capacity to make pragmatic use of that language in future settings.

The chapters of Part IV: International Case Studies, examine the role that culture, history, and policymaking play in shaping the practices of informal language learners at a national level. The chapters in this Part draw from case studies of informal language learning conducted in five nations or territories: Hong Kong, South Korea, Morocco, Sweden, and France. These five cases do not provide the basis for broad theorization about the role of macrosocial forces in shaping informal language learning, but they do demonstrate clearly that history, politics, and economics are potent forces that influence the frequency and the conditions in which informal learning of new languages is likely to take place.

In Chapter 18, Chun Lai and Boning Lyu report on the ways that, within the highly multilingual and multicultural context of Hong Kong, informal language learning has been embraced by both the government, through the funding of self‐access learning centers for new languages, and by youth, who form unique out‐of‐school learning ecologies that respond to the particular demands of their schools, their families, and their friends. Lai and Lyu also report that while Hong Kong youth's learning tends to favor receptive practices, it is nonetheless powerful and serves to mitigate some of the intensity of high‐stakes instruction in school. A different Asian context is presented in Chapter 19 by Ju Seong Lee, in his report on the English‐learning strategies of South Korean university students. According to Lee, Korean history and culture, combined with a test‐driven national English curriculum, reduce students' interest in engaging with English informally on their own. However, Lee's research also demonstrates that a small but increasing number of students do use and learn English through online gaming and other digital media, and among those who do he found a positive correlation between the extent of their informal learning and their proficiency in speaking and writing.

In a study similar to Lee's, in Chapter 20, Mark Dressman presents findings from a study of English learning among first‐year English majors in three public Moroccan universities. Morocco is a “nation of linguists,” where people speak at least four languages and proficiency in English is a matter of cultural identity and pride. Informal English learning is a widespread phenomenon there, and Dressman also reports a positive correlation between students' reported use of informal resources and TOEFL iBT (internet‐based test) speaking scores. However, proficiency in speaking English does not extend to proficiency in reading and writing, most likely because of issues related to students' literacy in Arabic and French.

Chapters 21 and 22 focus on informal language learning within European contexts. In Chapter 21, Pia Sundqvist describes the role of informal learning of languages within Swedish society. Sundqvist points out that although English is the dominant second language in Sweden, the country is, in fact, multilingual, with many speakers of languages from across Europe and, in recent years, a wide range of languages from the Middle East and Africa. Rather than describe the Swedish phenomenon as informal, Sundqvist prefers the term extramural, and notes that the activities of students learning digitally and online are beginning to extend beyond English to other languages, especially those of Asia, and that this extramural learning is beginning to challenge the formal language curriculum of schools. In Chapter 22, Meryl Kusyk reports on language learning in a very different European context, France. According to Kusyk, the reputation of the French for being poor language learners – a reputation reflected in assessments of second language fluency across Europe – has had a negative and enduring effect on French people's confidence about learning other languages. However, Kusyk also cites powerful evidence demonstrating that increasing engagement with digital media in other languages may be gradually changing both French attitudes and approaches toward second language learning.

Part V: Informal Learning and Formal Contexts presents six research‐based perspectives on the relationship between formal language instruction in schools and the practices of informal language learning. These chapters present a wide range of perspectives on the relationship between formal and informal learning. There are two basic issues explored by these chapters. The first is raised from the perspective of formal language education, and it leads to several related questions: How should classroom teachers and curriculum developers receive the news of informal language learning's increasing prevalence? Is this simply a trend – something that can be ignored because it will soon go away, is it perhaps another source of teaching ideas to spruce up the curriculum, or is it something more? The second issue derives from the possibility that informal learning is indeed “something more” than a trend that will pass or that can be easily absorbed into the formal curriculum, and it raises this question: If informal learning is “here to stay,” then what is its relationship to classroom learning? Does its presence mean that classrooms will become increasingly obsolete environments for language pedagogy, or does it mean that classrooms will need to adapt to or adopt many of the practices of informal learning, or could it mean that a more complex rapprochement between informal and formal learning might be arranged or developed, in which each remains aware of the other but each is left to engage in the practices that it is best designed to accomplish, so that complementarity between the merits of both informal and formal learning might occur, with powerful benefits for learners? The six chapters of this section do not answer these questions directly, but each provides grounds for informed and lively discussion of these issues.

Chapter 23, by Sarah J. McCarthey, Idalia Nuñez, and Chaehyun Lee discusses the phenomenon of translanguaging, or the combining of two languages within the same conversation or even utterance, as an informal learning and teaching activity in second language acquisition. In the literature on bilingual education in the United States, translanguaging is advocated by researchers as a way to dissolve hierarchical relations in classrooms between English and “an‐other” language, typically but not always Spanish. But in a broader context it may also be viewed as an engaging and playful bridge that builds meaning when one is learning a language but there are gaps in vocabulary and idiomatic expression that must be filled in conversation.

In Chapter 24, Katerina Zourou reviews the use of social networking in language learning, again with a focus on networking's potential in classroom contexts. Zourou notes that the term social networking encompasses a wide range of platforms, each with their own affordances and limitations. She warns that by its nature, social networking is a “wild” phenomenon, and one that resists “taming” within classroom contexts. Similarly, in Chapter 25, Binbin Zheng and Chin‐Hsi Lin focus on a practice that has great power within informal contexts to facilitate language acquisition: writing in digital and highly social contexts. These authors, however, are less concerned about the potential of bringing digital genres of writing into formal settings and “killing” their benefits in the process. They offer, in conclusion, multiple examples of successful incorporation of the informal into formal classrooms.

Like writing informally, reading informally has great benefits for language learners, and in Chapter 26 Doreen E. Ewert describes the multiple benefits of informal reading across an extensive range of texts, from websites and blogs to magazines, Wikipedia, and novels. The findings presented in this review of the research on extensive reading are unique in this Handbook in that they seem to apply equally to reading within formal classroom settings and the effects of reading informally out of school in a language that one is learning. Philip Hubbard, in Chapter 27, similarly focuses on classroom learning to ask how the informal language learning of students today can be taken into account within formal instruction. Hubbard has no illusions about whether informal practices can be instrumentally “added” or “incorporated” into the classroom without altering them in ways that decrease or eliminate their effectiveness. Instead, he advocates a “metacognitive” approach, in which teachers acknowledge their students' informal learning and work to help students build on it in their intentional classroom learning.

In the final chapter of this Part, Chapter 28, Dennis Murphy Odo provides a very thoughtful analysis of features of informal language learning and their implications for classroom curriculum and instruction. These are autonomy, the self‐directed learning afforded by technology, language identity, motivation, and metacognition. Odo argues that these features are not oppositional to classroom curriculum but can in fact be developed through classroom practices that encourage autonomy and participation in online communities both inside and outside of school. This chapter provides a powerful summary of many of the principles of informal language learning discussed not only in Part V but throughout the Handbook.

The final section of the Handbook, Part VI: The Present and Future of Informal Language Learning, takes a summative look at the implications of informal learning for language education, now and into the future. Chapter 29, by Helen Slatyer and Sarah Forget, examines the potential of digital translation, driven by advances in AI to make not only formal instruction but all language learning if not obsolete then not as pressing a concern in an age of globalization as it might be. Their review of the literature and brief “test” of three translation apps suggests that the technology has some distance to go before, or if it will ever, be able to translate simple phrases with near‐perfect accuracy, much less master the pragmatics of speech in context.

Robert Godwin‐Jones in Chapter 30 considers the potential of a broad range of new technologies to advance language learning and acquisition informally and in the classroom. His chapter provides a hopeful capstone to discussions about the informal–formal learning divide and the future of language acquisition in all its facets.

Chapter 31, the final chapter of the Handbook, is a special one. It is authored by Geoffrey Sockett and Denyze Toffoli, two pioneers in the field of informal language learning research. Their work is cited frequently by authors throughout this Handbook and is in many ways the foundation on which all our work in this area rests. We are grateful that when approached to write the final chapter of the Handbook they graciously agreed. Sockett and Toffoli's chapter is meant, however, not as a conclusion to the work presented here but to serve as a compass for future research and the development of new practices in language education. They ask guiding questions about terminology, about theoretical frameworks, and about relations between formal instruction and informal learning that are critical to the development of the field and to its implications for curriculum, instruction, and policy. Again, we are grateful for their contributions to research and especially to the Handbook.

Conclusion

In summary, the 31 chapters of this Handbook provide overwhelming evidence to support our opening statement in this Introduction, that we live in an historical period of unprecedented access and opportunity for informal language learning. An extraordinary array of digital media, combined with affordable transcontinental travel for many, although regrettably not all, learners has made it possible for nearly everyone with a desire or purpose to acquire almost any new language, at their own pace and in ways that are responsive to their needs and motivations.

At the same time, however, these chapters also shake one of the most enduring and basic beliefs about language education to its foundation. I refer here to a belief so tacit, so integral and fundamental to the infrastructure of language education today in nearly all its forms that it has escaped serious challenge or interrogation for hundreds of years. This belief is, simply, that learning a new language past childhood is a laborious, time‐consuming, and often impossible task for most people, and one that requires not only great effort but the tutelage of a speaker of that language who has the skill and knowledge to teach it to others through systematic and sometimes unavoidably tedious processes.

The evidence of this Handbook upends this basic presumption about language acquisition and suggests that the entire edifice of language education around the world today could be in jeopardy. For example, what if the evidence of learners' own experiences of informal language learning and the research evidence begins to challenge traditional beliefs about the difficulties of adolescent and adult language acquisition? What if these challenges become increasingly public? And what if it begins to seem instead what some learners and progressive teachers have suspected all along but never dared to suggest openly: That in many cases formal language instruction actually may impede language acquisition, so that the worst way to learn and become functional in a new language may be in a classroom setting?

As language educators and researchers, the prospect of this development is both thrilling and a bit disconcerting. It is thrilling because as a phenomenon, informal language learning, especially within digital contexts, represents the most significant advance in foreign language education in at least a millennium, and one that is grounded in principles of the democratization of knowledge. It is disconcerting because, as only one of many areas of learning available out of school, it potentially threatens the entire structure of schooling and of education around the world.

Consider, for example, the impact that online learning has already had in higher education, with the development first of masters‐level degree programs, then undergraduate and now even professional and doctoral programs. The argument might be made that these are not “informal,” because they remain organized courses of instruction. They are, however, typically “asynchronous,” meaning that learners can “attend” at times preferable to them and wherever they choose. Consider the way that the expansion of such programs, as they extend into secondary and then even primary schools will change what it means to “teach” a language or any other subject for that matter. And then consider the direction that some professional certification programs are moving in, especially in the United States, where, for example, once past initial licensing, to become “endorsed” to teach an additional subject in a public school in Illinois or Arizona now means that all one needs to do is pass a content test certifying one's knowledge of history, mathematics, a foreign language, or almost any other school subject. Subjects that are considered “easy to assess,” like mathematics or foreign languages may soon not require coursework at all to receive course credit, as long as one can pass a test certifying knowledge of facts. When exam‐based certification programs replace process‐based programs of instruction, some individuals may be empowered; but longer term social, economic, and educational consequences for society could be catastrophic.

Let us hope, however, that this does not happen. How could it not? I will end this introduction to the Handbook by suggesting that one way is for formal language educators and educators in general to begin to take the lessons of informal language learning seriously, not as a threat but as an invitation to rethink and revitalize formal language curriculum in some radical ways. Only by “adding value” to formal instruction will it be able to not simply survive but maintain its influence within society in the coming century and millennium. Let us hope, then, that the lessons of the 31 chapters of this volume will be read as a starting point on that adventure.

REFERENCES

1. d'Anglejan, A. (1978). Language learning in and out of classrooms. In: Understanding Second and Foreign Language Learning, Understanding Second and Foreign Language Learning (ed. C.J. Richards), 218–237. New York: Newbury House Publishers.
2. Ellis, R. (1980). Classroom interaction and its relation to second language learning. RELC Journal 11 (2): 29–48.
3. Ellis, R. (1982). Informal and formal approaches to communicative language teaching. ELT Journal 36 (2): 73–81.
4. Krashen, S.D. (1976). Formal and informal linguistic environments in language acquisition and language learning. TESOL Quarterly 10 (2): 157–168.
5. Lee, J.S. and Dressman, M. (2018). When IDLE hands make an English workshop: informal digital learning of English and language proficiency. TESOL Quarterly 52 (2): 435–445.
6. Toffoli, D. and Sockett, G. (2015). University teachers' perceptions of online informal learning of English (OILE). Computer Assisted Language Learning 28 (1): 7–21.