“…Since the 1990s, conspicuous strides have been taken in order to define current practices and help improve the quality of bilingual education. Numerous studies have been published on teachers, students and parents' views on bilingual education (Pérez Cañado, 2017;Pena & Porto, 2008), learning and acquisition of vocabulary and lexicon (Jiménez Catalán & Agustín, 2017;Tragant et al 2016;Sylvén & Ohlander, 2014;Jiménez, Ruiz de Zarobe & Cenoz, 2006), students' L2 proficiency (Pérez Cañado, 2018;Merino & Lasagabaster, 2018;Ackerl, 2007;Mewald, 2007;Serra, 2007;Admiraal et al 2006) and L1 proficiency (Merisuo-Storm, 2007), students' cognitive development (Jäppinen, 2005), teachers' linguistic and methodological training needs (Pérez Cañado, 2016;Fernández & Halbach, 2011;Martín del Pozo, 2011;Rubio Mostacero, 2009), students' starting age (Van de Craen et al 2007;Lorenzo et al 2009), motivation (Lasagabaster & López Beloqui, 2015), amongst others.…”