This book focuses on Portuguese as an additional language and its young learners in three case studies within the Portuguese-speaking world: Portuguese as a second language in Cape Verde, Portuguese as a heritage language in Switzerland and Portuguese as a foreign language in Macao SAR. The term “additional language” is used as an umbrella term for all three contexts. An analysis of these three case studies is presented, with a focus on the organization of  explicit and implicit language policies with regards to population mobility and also motivational issues, language attitudes and language use by the sample population.