Christoph Gabriel 
, Jonas Grünke
Even though there were already calls around the turn of the millennium for the heritage languages of learners to be included in foreign-language teaching (e.g., Gogolin 1994, Hu 2003), the acquisition of phonology in the context of migration-induced multilingualism is still an emerging area of research in both linguistics and language pedagogy. Based on recent studies on the acquisition of L3 French and Spanish phonology by heritage bilinguals (e.g., Gabriel et al. 2014/2018/2022, Grünke & Gabriel 2022), it is posited that the acquisition of a foreign language’s sound system is enhanced by metalinguistic and phonological awareness. Furthermore, such awareness can be fostered by imparting declarative knowledge regarding the similarities and differences between the languages of the learners’ linguistic background and the foreign languages they learn. Whether interventions can foster facilitative transfer from a heritage language onto the target language seems to be contingent upon three factors: (i) the maintenance of the relevant feature in the learner’s heritage language, (ii) the degree of activation of the learner’s heritage language during the learning process, and (iii) the perceptual salience of the feature at issue. In the light of insights from phonetic learning, we argue that intensive pronunciation training over a longer period is required to support and consolidate the positive, sometimes short-term effects found in the studies.