For centuries, languages have been changing and evolving in complex, systematic ways. The study of past stages of a linguistic system and the overarching linguistic patterns characterizing the arc of change over time characterize the field of linguistics known as historical linguistics. Historical linguistics serves to illuminate both the sources and earlier phonetic and morphosyntactic features of a given language and the present trajectories and modern features of those same systems. This has implications for Second Language Acquisition. Indeed, existing literature suggests that instruction in various aspects of historical linguistics correlates positively with increased confidence, motivation, global competence, and multicultural identity. This study explored the effects of introductory historical linguistics exposure on the L2 Motivational Self as defined by Dornyei (2005) and revisualized for multilingual learners by Ushioda (2017) and Lasagabaster (2014), among others. After a one-week treatment period, qualitative and quantitative data were analyzed to determine if changes could be detected in middle and high school language learners' levels of motivation, enjoyment, and sense of identity in the foreign language classroom. Quantitative results revealed significant results in the areas of self-efficacy and metalinguistic awareness. Qualitative analysis revealed strong support for increased L2 enjoyment, L2 motivation, and self-efficacy, and revealed moderate support for lowered L2 anxiety and higher self-confidence. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]