This study examines acoustic vowel data from a group of 88 Finnish and Italian Americans from Michigan’s Upper Peninsula (UP), stratified by task, heritage, age, sex, and educational attainment. Results reveals four sociolinguistic patterns in Michigan’s UP English regarding lingering substrate and encroaching exogenous norms. First, the presence of a systematic structural difference of the low and back vowels and the presence of the monophthongized /o/is argued to result from substratal influence. Additionally, the fully realized low-back merger and the conditionally compromised Canadian raising of /αi/and /α℧/are older features originating from Canadian English. Furthermore, apparent-time evidence in this rural community indicates a developing change in progress in which front lax vowels participate in the Canadian Shift. This change in progress toward Canadian-like norms is led by females of successively younger generations. Finally, the existence of these new local norms in the younger UP speakers’ systems for both the reading passage and the word list data indicates that such norms are well established and largely below these speakers’ awareness in various speech styles. This study compares subgroups within the larger speech community and reveals much about the impact of ethnic-heritage languages on a rurally spoken American English variety while simultaneously showing the exogenous influences of neighboring regional varieties.