This book explores young children's language acquisition in multilingual households through an original longitudinal study of the author's own children and interviews with members of other Korean-English families. The study investigates how multilingual children not only acquire multiple languages (verbal communication) but also acquire multiple strategies of non-verbal communication. In the process, it is also revealed that parents learn from children, collaboratively shaping the language of their family together in a manner that is between and beyond languages and cultures. The book explores the different types and frequency of non-verbal behaviours acquired by multilingual children and reveals how multilingual families use a range of multimodal resources to communicate effectively in a way that creates solidarity. The results of this longitudinal study are discussed within the paradigm of translanguaging and provide insight into an underrepresented multilingual population. With accompanying online videos, this book offers rich multimodal family interaction data for students and researchers interested in multilingualism, family language practices, and first and second language acquisition.