This collection of studies investigates the individual, micro-psychological, and macro-societal factors that promote or discourage the development of child and young adult heritage language learners’ spoken and written skills in East Asian languages (Chinese, Japanese, and Korean). The research presented in this book is based on empirical data from various learning and social settings in the United States and Canada. The contributors are themselves mostly from East Asian immigrant backgrounds and have worked closely with students from such backgrounds. This book also speaks to the needs for future research within East Asian communities that will (a) promote East Asian heritage language development in applied linguistics, (b) encourage parental, community, and national support for East Asian heritage language development, and (c) improve the teaching of oral and written skills for heritage learners of East Asian languages in various educational settings.