Heritage speakers are a fascinating group of bilinguals with a unique profile. Living abroad as immigrants of the second generation, they speak the language of their own speech community (the heritage language) at home, and the societally dominant language in most other domains. What exactly they know about their heritage language continues to fascinate the research community as well as teachers and other practitioners working with this group. The different contributions cover a large variety of studies into heritage languages spoken in Europe and North America (including Chinese, Norwegian,...