Introduction to the special issue on Heritage languages & Bilingualism

This special issue of the Nordic Journal of Linguistics is dedicated to heritage languages and bilingualism. Heritage languages are naturalistically acquired languages, but not the dominant language in the broader society (Rothman 2009:156) and over the last two decades, there has been a growth in research to languages in this specific bilingual setting (see Montrul 2016, Polinsky 2018 for overviews). However, the study of bilingualism and language contact has contributed to our understanding of the formal and social nature of language long before the term ‘heritage language’ was used (especially Haugen 1953, Weinreich 1953). The field of heritage language linguistics contributes empirically and theoretically to discussions concerning language acquisition and maintenance throughout the lifespan, linguistic processes, and language variation and linguistic knowledge. For example, the different and varied input that heritage speakers receive affects their acquisition of linguistic representations and changes in language use over time may affect how speakers access those representations in comprehension and production of their heritage language (Putnam et al. 2019). Acquisition and maintenance are recurrent factors in explaining the often-observed differences between heritage speakers and monolingual homeland speakers of the language. In addition, the particular sociopolitical contexts in which heritage languages are spoken offer fertile ground for investigations into a wide range of social factors that affect language maintenance and shift (Wilkerson & Salmons 2008, Frey 2013, Aalberse et al. 2019), as well as language changes related to community-wide bilingualism (e.g. Haugen 1953, Nagy 2011). Finally, the study of heritage languages can provide insights for our formal linguistic theories (Benmamoun et al. 2013, Scontras et al. 2015, Lohndal et al. 2019), although this has only been pursued relatively recently. The Scandinavian heritage languages in the US have received renewed attention in the last decade (e.g. the chapters in Johannessen & Salmons 2015, Page & Putnam 2015). For this special issue, we welcomed manuscripts on both Nordic and nonNordic languages to represent the breadth of the field of heritage languages. In addition, we believe that including a large variety of languages into our studies advances the field by promoting opportunities for comparing and contrasting heritage