In this article, I analyse the programme and pedagogy of "Karmelo Ikastola," a Basque immersion school that promotes parental involvement and language use within the family. The "Karmelo" case is noteworthy due to its success at effectively promoting the use of Basque among students inside and outside the school along with its promotion of curricular separation between L1 native speakers and L2 learners of Basque. With support from the EBETE language cooperative, "Karmelo" launched an innovative approach to increase parental involvement in 2008. The school considers distinct pedagogical frameworks for different profiles of parents: Basque-speaking parents, mixed families (in which only one of the parents speaks Basque), and Spanish-speaking parents. The "Karmelo" programme also fosters parental participation and engagement via curricular adaptations that differentiate the needs of L1 and L2 speakers. The focus group data offer insights into the programme's approach to language instruction and acquisition, highlighting the role that linguistic attitudes and socialisation play during the various stages of L2 acquisition.