“…As has been shown in a number of recent studies (e.g., Montrul, 2008 ; Pascual y Cabo et al, 2012 ; Benmamoun et al, 2013 ; Kupisch et al, 2014 ; Johannessen and Salmons, 2015 ; Polinsky, 2015b ; Larsson and Johannessen, 2015a , b ), heritage languages can provide important insights into the nature of language acquisition, the linguistic effects of bilingualism across the lifespan of the speaker, and the principles behind linguistic change 1 . In earlier work (Larsson and Johannessen, 2015a , b ; Larsson et al, 2015 ), we have identified four different factors that affect the development of the Scandinavian heritage language in America: contact between Scandinavian and English, contact between Scandinavian dialects (leading to dialect leveling and koineization), incomplete acquisition due to limited input and a language shift around the time of school start, and attrition. Attrition here refers to the loss of linguistic abilities that were once present in the speaker, due to lack of language use.…”