Since the publication of Mehisto et al. (2008) and Coyle et al. (2010), CLIL research has mushroomed and appeared in books, book chapters, disserta- tions, research articles, reflective pieces, projects and lesson plans. This comes to show that CLIL is appealing to researchers as well as teachers and that it is growing not only in its theoretical rationale but also in systematised informed practice. It also reveals that CLIL can become stronger if practitioners and researchers work collaboratively and strive for integrating practice and theory (Anderson, McDougald, & Cuesta Medina, 2015). The intersection between theory and implementation can be evidenced through the different research frameworks utilised as we can find action research (Banegas, 2018), experi- ments (Piesche, Jonkmann, Fiege, & Keßler, 2016), and quantitative/quasi- experimental studies with large samples (Pérez Cañado, 2018b), comparative (Jiménez Catalán & Agustín Llach, 2017), and longitudinal studies (Pérez Cañado, 2018c).
The CLIL research agenda is varied and includes areas such as curriculum development (e.g., Carrió-Pastor, 2020), assessment (e.g., chapters “Assessing Students’ Learning of History Content in Spanish CLIL Programmes: A Content and Language Integrated Perspective” and “Current Practice and
Challenges of Assessment in CLIL in a Japanese University Context”, this volume; Otto & Estrada, 2019), scaffolding (e.g., Mahan, 2020), classroom discourse (e.g., chapter “The Role of the Essential Question in Eliciting Critical Thinking in CLIL Classes at a Japanese University”, this volume; Li
& Zhang, 2020), policy for and challenges in implementation (e.g., chapter
“Sistemas Educacionais (SE) and CLIL Developments in Brazil: From Promises to Prospects”, this volume; Pimentel Siqueira, Landau, & Albuquerque Paraná, 2018), materials (e.g., chapter “Language- Driven CLIL in Primary Education: An Analysis of General English Coursebooks in Argentina” 12, this volume; Moore & Lorenzo, 2015), interculturality (e.g., chapter
“Developing Intercultural Competence: A Comparison of CLIL and Language Majors Before and After Industrial Placements”, this volume; Porto, 2018), teacher development (e.g., chapters “The Role of CLIL in Learning About TESOL: Reflections from an Australian Master of TESOL Course”, “CLIL- ising EMI: An Analysis of Student and Teacher Training Needs in Monolingual Contexts”, “Top- Down and Bottom- Up CLIL Teacher Development: Lessons Learned from Austrian In- Service CLIL Teacher CPD”, and “Developing the C in Content and Language Integrated Learning: Teacher Preparation That Builds Learners’ Content Knowledge and Academic Language Through Teacher Collaboration and Integrated Pedagogical Training”, this volume; He
& Lin, 2018), psychological factors such as identity, motivation or emotions (e.g., Talbot, Gruber, & Nishida, 2021) and teachers’ and learners’ percep- tions and attitudes (e.g., Fazzi & Lasagabaster, 2020; McDougald & Pissarello, 2020) among other topics that attract research attention.
These areas mentioned above share a common aim: understanding how learners can successfully develop subject-matter knowledge in an additional language and L2 language systems (e.g., grammar, vocabulary) together with linguistic and cognitive skills (Pérez Cañado, 2020) through the CLIL approach(es). The research agenda covers this interest across all levels of for- mal education: kindergarten (Riera Toló, 2017; Švecová, 2011), primary (Martín-del Pozo & Rascón-Estébanez, 2021; Otwinowska & Foryś, 2017;
Pladevall-Ballester & Vallbona, 2016), secondary (Bellés-Calvera, 2018;
Gallagher & Colohan, 2017; Ikeda, 2013), and higher education (Fortanet- Gómez, 2013; Ruiz de Zarobe & Lyster, 2018; Sendur, van Boxtel, & van Drie, 2021; Yang, 2016). These studies agree that CLIL contributes to adding meaningfulness to the learners’ experience as they can use an additional lan- guage to talk about curriculum content and make sense of their practice at different levels and contexts.
Below, we discuss CLIL research in more detail regarding the following areas: (1) motivation, (2) translanguaging, (3) genre and language awareness, and (4) explicit and implicit language learning.
Motivation has been one of the most researched areas in CLIL, whether it is content-driven (e.g., chapter “Authenticity and Motivation in CLIL:
Creating a Meaningful Purpose by Experiencing the Language in Use”, this volume; Doiz, Lasagabaster, & Sierra, 2014) or language-driven (e.g., Banegas, 2013). According to Lasagabaster (2019), studies coincide in that learners achieve better results in foreign language learning when it is integrated with content instruction. According to learners, their motivation is enhanced because they can contribute to the CLIL lesson and they build new knowl- edge in an L2 based on what they have learnt in their L1 in mainstream lan- guage of instruction. In this regard, it has been highlighted (Coyle et al., 2010) that CLIL does not mean learning the same content twice; on the contrary there should be an element of newness and therefore they suggest that lessons move from familiar language to familiar content and new lan- guage to new content and that all activities are contextualised in the content in focus. Therefore, scaffolding and attention to ZPD enhance learner moti- vation in a CLIL environment.
While the content element in CLIL is straightforward (as there is general consensus that it must come from the school curriculum, see above), language is more complex an element to tackle. For example, from a content-driven perspective, Ball et al. (2015) argue that CLIL is not for all and that it works best with learners with higher L2 levels. The reason is, quite understandably, that if language needs to be simplified to match learners’ elementary level of English, content is also simplified, thus running the risk of becoming too simple and therefore demotivating. On the other hand, one could also argue that the students’ interest in the content could be a motivator even for stu- dents with limited L2 proficiency or basic knowledge of the content, creating an opportunity to focus on vocabulary and language connected to the learn- ing of concepts in the subject, language of learning (Coyle et al., 2010).
Translanguaging as an approach goes beyond code-switching and it involves multiple discursive practices in which bilinguals engage in order to make sense of their bilingual worlds (García, 2009). In translanguaging, speakers treat the languages they use as one. In the CLIL literature, Nikula and Moore (2019) summarise the origin and development of the term and observe that in CLIL lessons translanguaging has evolved from being a pedagogical strat- egy to becoming a generalised discursive practice. Recent studies (e.g., Karabassova & San Isidro, 2020; Wu & Lin, 2019) show that a positive effect of translanguaging in CLIL is that the main languages spoken in the
classroom have equally high status and therefore the first language or language of schooling becomes a useful tool for learning and developing cognitive skills.
Researchers have also been interested in genre and language awareness in CLIL and both content and language teachers, and learners are directed to pay attention to these two areas (Llinares, Morton, & Whittaker, 2012; Ruiz de Zarobe, 2017). Studies (e.g., Llinares & Pascual Peña, 2015; Lo & Jeong, 2018) have demonstrated that when learners are guided to identify and follow the specific genres, grammar and lexis of an academic discipline such as his- tory or art, they exhibit an improvement in the transition between Basic Interpersonal Communication Skills (BICS) and Cognitive Academic Language Proficiency (CALP) (Cummins, 1979), CALP (Cummins, 1979), between oracy and literacy, and between subject-specific language and general academic language. For example, Lo and Jeong (2018) report that genre- based pedagogy, which includes systematic guided discovery and inductive teaching strategies based on real-life texts and examples, has a positive effect on learners’ understanding of how languages operate according to functions and purposes. In addition, language awareness promotes learners’ own reflec- tions on their progress in language learning (Lasagabaster & Doiz, 2016).
Research has also demonstrated that having clear language aims and an explicit linguistic component in CLIL lessons helps learners develop their language skills and become proficient L2 users (e.g., Arias, 2021; Genesee &
Hamayan, 2016). To ensure the presence of systematic and explicit language learning, Ball et al. (2015) suggest that a CLIL syllabus can be constructed by paying attention to three dimensions: concepts, procedures, and language.
According to recent studies (e.g., Banegas, 2020; Martín-del Pozo & Rascón- Estébanez, 2021), this model may help teachers become aware that language cannot be accidental or peripheral; it deserves careful planning in the CLIL lesson. In addition, the model allows the incorporation of the language trip- tych as it enables teachers to attend to different dimensions of language learn- ing together with the procedures and activities that will scaffold content and language instruction.
All in all, this section shows that even a cursory review of CLIL research shows that CLIL has been examined from a whole array of educational, lin- guistic, and psychological perspectives, given the spread and ramified devel- opment of CLIL across diverse settings around the world. In this volume, we have only included a small number of CLIL research areas since it would be almost impossible to illustrate all of them.