Using loanword data from Haugen (1953), this paper investigates variation in vowel integrations of English loanwords in the Norwegian among 19th century Norwegian immigrants to the United States, as first-language Norwegian and second-language English speakers. Previous research, most notably Flege (1995), has argued that speakers make use of L1 categories that are the most similar to the integrated L2 sound. In contrast, this research argues that the “most similar,” as well as less similar but attested, L1 integrated phonemes can be understood through the Lahiri and Reetz (2002) Underspecified Recognition model, where phonetic features of L2 input sounds are mapped onto hierarchically organized L1 distinctive features (i.e., Dresher, 2009).