Admiraal, W., Westhoff, G. and de Bot, K. (2006) Evaluation of bilingual secondary education in the Netherlands: students’ language proficiency in English. Educational Research and Evaluation 12(1): 75–93. https://doi.org/10.1080/13803610500392160

Baerman, M., Brown, D. and Corbett, G.G. (eds) (2015) Understanding and Measuring Morphological Complexity. New York: Oxford University Press. https://doi.org/10.1093/acprof:oso/9780198723769.001.0001

Bardovi-Harlig, K. (1992) A second look at T-unit analysis: reconsidering the sentence. TESOL Quarterly 26(2): 390–5. https://doi.org/10.2307/3587016

Brezina, V. and Pallotti, G. (2019) Morphological complexity in written L2 texts. Second Language Research 35(1): 99–119. https://doi.org/10.1177/0267658316643125

Bruton, A. (2011) Is CLIL so beneficial, or just selective? Re-evaluating some of the research. System 39(4): 523–32. https://doi.org/10.1016/j.system.2011.08.002

Bruton, A. (2013) CLIL: some of the reasons why … and why not. System 41: 587–97. https://doi.org/10.1016/j.system.2013.07.001

Bruton, A. (2017) Questions about CLIL which are unfortunately still not outdated: a reply to Pérez-Cañado (2017). Applied Linguistics Review. https://doi.org/10.1515/applirev-2017-0059

Bulon, A., Hendrikx, I, Meunier, F. and Van Goethem, K. (2017) Using global complexity measures to assess second language proficiency. Comparing CLIL and non-CLIL learners of English and Dutch in French-speaking Belgium. Papers of the Linguistic Society of Belgium 11(1): 1–25.

Bulté, B. (2013) The development of complexity in second language acquisition. A dynamic systems approach. Unpublished doctoral dissertation. University of Brussels (VUB), Brussels.

Bulté, B. and Housen, A. (2012) Defining and operationalising L2 complexity. In A. Housen, F. Kuiken and I. Vedder (eds) Dimensions of L2 Performance and Proficiency. Investigating Complexity, Accuracy and Fluency in SLA 21–46. Amsterdam: John Benjamins. https://doi.org/10.1075/lllt.32.02bul

Bulté, B. and Housen, A. (2014) Conceptualizing and measuring short-term changes in L2 writing complexity. Journal of Second Language Writing 23(4): 21–45. https://doi.org/10.1016/j.jslw.2014.09.005

Bulté, B. and Housen, A. (2018) Syntactic complexity in L2 writing: Individual pathways and emerging group trends. International Journal of Applied Linguistics 28(1): 1–18. https://doi.org/10.1111/ijal.12196

Bulté, B., Housen, A., Pierrard, M. and Van Daele, S. (2008) Investigating lexical proficiency development over time – the case of Dutch-speaking learners of French in Brussels. Journal of French Language Studies 18: 277–98. https://doi.org/10.1017/s0959269508003451

Cenoz, J., Genesee, F. and Gorter, D. (2014) Critical Analysis of CLIL: taking stock and looking forward. Applied Linguistics 35(3): 243–62. https://doi.org/10.1093/applin/amt011

Coyle, D., Hood, P. and Marsh, D. (2010) CLIL. Content and Language Integrated Learning. Cambridge: Cambridge University Press.

Dalton-Puffer, C. (2011) Content-and-language integrated learning: from practice to principles? Annual Review of Applied Linguistics 31: 182–204. https://doi.org/10.1017/S0267190511000092

Dalton-Puffer, C. (2017) CLIL in Practice – What does the Research Tell Us? Web publication, Goethe Institute. https://www.goethe.de/en/spr/unt/kum/clg/20984546.html

Dalton-Puffer, C., Nikula, T. and Smit, U. (eds) (2010) Language Use and Language Learning in CLIL Classrooms. Amsterdam: John Benjamins. https://doi.org/10.1075/aals.7

De Clercq, B. and Housen, A. (2019) The development of morphological complexity: A cross-linguistic study of L2 French and English. Second Language Research 35(1): 71–98. https://doi.org/10.1177/0267658316674506

Edwards, A. (2014) The progressive aspect in the Netherlands and the ESL/EFL continuum. World Englishes 33: 173–94. https://doi.org/10.1111/weng.12080

Gené-Gil, M., Juan-Garau, M. and Salazar-Noguera, J. (2015) Development of EFL writing over three years in secondary education: CLIL and non-CLIL settings. Language Learning Journal 43(3): 286–303. https://doi.org/10.1080/09571736.2015.1053278

Guiraud, P. (1959). Problèmes et méthodes de la statistique linguistique. Dordrecht: Reidel.

Heatley, A., Nation, P. and Coxhead, A. (2002) RANGE and FREQUENCY programs. Retrieved on 18 January 2018 from http://www.victoria.ac.nz/lals/staff/paul-nation/nation.aspx.

Housen, A. (2012) Time and amount of L2 contact inside and outside the school: Insights from the European schools. In C. Muñoz (ed.) Intensive Exposure Experiences in Second Language Learning 111–40. Clevedon, UK: Multilingual Matters. https://doi.org/10.21832/9781847698063-009

Housen, A. and Kuiken, F. (2009) Complexity, accuracy, and fluency in second language acquisition. Applied linguistics 30(4): 461–73. https://doi.org/10.1093/applin/amp048

Housen, A., Schoonjans, E., Janssens, S., Welcomme, A. and Pierrard, M. (2011) Conceptualizing and measuring the impact of contextual factors in instructed SLA – The role of language prominence. International Review of Applied Linguistics in Language Teaching 49(2): 83–112. https://doi.org/10.1515/iral.2011.005

Jarvis, S. (2013) Capturing the diversity in lexical diversity. Language Learning 63(s1): 87–106. https://doi.org/10.1111/j.1467-9922.2012.00739.x

Jenniskens, T., Leest, B., Wolbers, M., Krikhaar, E., Teunissen, C., de Graaff, R., Unsworth, S. and Coppens, K. M. (2018) Evaluatie pilot tweetalig primair onderwijs: vervolgmeting schooljaar 2016/17. Report. Retrieved 15 April 2018 from https://dspace.library.uu.nl/handle/1874/376282.

Kyle, K. (2016) Measuring syntactic development in L2 writing: fine grained indices of syntactic complexity and usage-based indices of syntactic sophistication. Doctoral dissertation. Retrieved 22 February 2018 from http://scholarworks.gsu.edu/alesl_diss/35.

Lahuerta Martínez, A. C. (2015) The written competence of Spanish secondary education students in bilingual and non-bilingual programs. Porta Linguarium 24: 47–61.

Lázaro, A. and García Mayo, M. (2012) L1 use and morphosyntactic development in the oral production of EFL learners in a CLIL context. International Review of Applied Linguistics in Language Teaching 50(2): 135–60.

Lindgren, E. and Muñoz, C. (2013) The influence of exposure, parents, and linguistic distance on young European learners’ foreign language comprehension. International Journal of Multilingualism 10: 105–29. https://doi.org/10.1080/14790718.2012.679275

Long, M. H. (1991) Focus on form: a design feature in language teaching methodology. In K. de Bot, R. B. Ginsberg and C. Kramsch (eds) Foreign Language Research in Cross-cultural Perspective 39–52. Amsterdam: John Benjamins. https://doi.org/10.1075/sibil.2.07lon

Lorenzo, F., Moore, P. and Casal, S. (2011) On complexity in bilingual research: the causes, effects, and breadth of content and language integrated learning – a reply to Bruton (2011). Applied Linguistics 32(4): 450–5. https://doi.org/10.1093/applin/amr025

MacWhinney, B. (2000) The CHILDES Project: Tools for Analyzing Talk. Hillsdale, NJ: Lawrence Erlbaum.

Madlener, K. (2015) Frequency Effects in Instructed Second Language Acquisition. Berlin: de Gruyter. https://doi.org/10.1515/9783110405538

Malvern, D., Richards, B. J., Chipere, N. and Durán, P. (2004) Lexical Diversity and Language Development. New York: Palgrave Macmillan. https://doi.org/10.1057/9780230511804

Martínez Adrián, M. and Gutiérrez Mangado, M. (2015a) Is CLIL instruction beneficial in terms of general proficiency and specific areas of grammar? Journal of Immersion and Content-Based Language Education 31(1): 51–76. https://doi.org/10.1075/jicb.3.1.03adr

Martínez Adrián, M. and Gutiérrez Mangado, M. (2015b) L1 use, lexical richness, accuracy and syntactic complexity in the oral production of CLIL and NON-CLIL learners of English. Atlantis. Journal of the Spanish Association for Anglo-American Studies 37(2): 177–99.

McCarthy, P. and Jarvis, S. (2010) MTLD, vocd-D, and HD-D: a validation study of sophisticated approaches to lexical diversity assessment. Behavior Research Methods 42(2): 381–92. https://doi.org/10.3758/BRM.42.2.381

Michel, M., Murakami, A., Alexopolou, T. and Meurers, D. (2019) Effects of task type on morphosyntactic complexity across proficiency: evidence from a large learner corpus of A1 to C2 writings. Instructed Second Language Acquisition 3(2): 124–52.

Norris, J. M. and Ortega, L. (2009) Towards an organic approach to investigating CAF in instructed SLA: the case of complexity. Applied Linguistics 30(4): 555–78. https://doi.org/10.1093/applin/amp044

Olive, T. (2012) Working memory in writing. In V. Berninger (ed.). Past, Present, and Future Contributions of Cognitive Writing Research to Cognitive Psychology 485–503. New York: Psychology Press.

Ortega, L. (2003) Syntactic complexity measures and their relationship to L2 proficiency: a research synthesis of college-level L2 writing. Applied Linguistics 24(4): 492–518. https://doi.org/10.1093/applin/24.4.492

Pallotti, G. (2015) A simple view of linguistic complexity. Second Language Research 31(1): 117–34. https://doi.org/10.1177/0267658314536435

Pérez-Cañado, M. L. (2012) CLIL research in Europe: past, present, and future. International Journal of Bilingual Education and Bilingualism 15(3): 315–41. https://doi.org/10.1080/13670050.2011.630064

Pérez-Cañado, M. L. (2017) Stopping the ‘pendulum effect’ in CLIL research: finding the balance between Pollyanna and Scrooge. Applied Linguistics Review 8(1): 79–99. https://doi.org/10.1515/applirev-2016-2001

Pérez-Vidal, C. and Roquet, H. (2015) The linguistic impact of a CLIL science programme: an analysis measuring relative gains. System 54: 80–90. https://doi.org/10.1016/j.system.2015.05.004

Rescher, N. (1998) Complexity: A Philosophical Overview. London: Transaction Publishers.

Robinson, P. (2001) Task complexity, cognitive resources, and syllabus design: a triadic framework for examining task influences on SLA. In P. Robinson (ed.) Cognition and Second Language Instruction (pp. 287–318). Cambridge: Cambridge University Press. https://doi.org/10.1017/CBO9781139524780.012

Robinson, P. (2007) Criteria for grading and sequencing pedagogic tasks. In M.P. Garcia Mayo (ed.). Investigating Tasks in Formal Language Learning 7–27. Clevedon: Multilingual Matters. https://doi.org/10.21832/9781853599286-004

Ruiz de Zarobe, Y. (2010) Written production and CLIL: an empirical study. In C. Dalton-Puffer, T. Nikula and U. Smit (eds) Language Use and Language Learning in CLIL Classrooms 191–210. Amsterdam: John Benjamins. https://doi.org/10.1075/aals.7.10rui

Ruiz de Zarobe, Y. (2011) Which language competencies benefit from CLIL? An insight into applied linguistics research. In Y. Ruiz de Zarobe, J. M. Sierra and F. Gallardo del Puerto (eds) Content and Foreign Language Learning. Contributions to Multilingualism in European Contexts 129–53. Bern: Peter Lang. https://doi.org/10.3726/978-3-0351-0171-3

Rumlich, D. (2016) Evaluating Bilingual Education in Germany: CLIL Students’ General English Proficiency, EFL Self-concept and Interest. Frankfurt: Peter Lang.

Schmidt, R. (1990) The role of consciousness in second language learning. Applied Linguistics 11(2): 129–58. https://doi.org/10.1093/applin/I.2.129

Skehan, P. (1998) A Cognitive Approach to Language Learning. Oxford: Oxford University Press. https://doi.org/10.1177/003368829802900209

Spada, N. (1997) Form-focused instruction and second language acquisition: a review of classroom and laboratory research. Language Teaching 30: 73–87. https://doi.org/10.1017/S0261444800012799

Sundqvist, P. and Sylvén, L. K. (2016) Extramural English in Teaching and Learning: From Theory and Research to Practice. London: Palgrave Macmillan. https://doi.org/10.1057/978-1-137-46048-6

Tomasello, M. (2003) Constructing a Language: A Usage-based Theory of Language Acquisition. Cambridge, MA: Harvard University Press.

Verbeke, G. and Molenberghs, G. (2000) Linear Mixed Models for Longitudinal Data. New York: Springer. https://doi.org/10.1007/978-1-4419-0300-6

Verspoor, M., de Bot, K. and Xu, X. (2015) The effects of English bilingual education in the Netherlands. Journal of Immersion and Content-Based Language Education 3(1): 4–27. https://doi.org/10.1075/jicb.3.1.01ver

Verspoor, M., Schmid, M. and Xu, X. (2012) A dynamic usage based perspective on L2 writing. Journal of Second Language Writing 21(3): 239–63. https://doi.org/10.1016/j.jslw.2012.03.007

Verspoor, M., Schuitemaker-King, J., Van Rein, E., De Bot, K. and Edelenbos, P. (2010) Tweetalig onderwijs: vormgeving en prestaties. Report. Retrieved on 20 February 2018 from https://www.nuffic.nl/documents/220/tweetalig-onderwijs-vormgeving-en-prestaties.pdf

Wolfe-Quintero, K., Inagaki, S. and Kim, H.-Y. (1998) Second Language Development in Writing: Measures of Fluency, Accuracy, and Complexity. Honolulu: University of Hawaii, Second Language Teaching and Curriculum Center.