Historical Glottometry, introduced by Alexandre François (2014), is a wave-based quantitative approach to language subgrouping that is used to calculate the overall strength of a linguistic subgroup using metrics that capture the contributions of linguistic innovations of various scopes to language diversification, in consideration of the reality of their distributions. It primarily achieves this by acknowledging the contribution of areal diffusion to language diversification, which has traditionally been overlooked in cladistic (tree-based) models. In this thesis, the development of the Germanic language family, from the breakup of Proto-Germanic to the latest period of the early attested daughter languages (namely Gothic, Old English, Old Norse and Old High German), is accounted for using Historical Glottometry. It is shown that this approach succeeds in accounting for several smaller, nontraditional subgroups of Germanic by accommodating the linguistic evidence unproblematically where a cladistic approach would fail. v ACKNOWLEDGMENTS I would like to thank first and foremost Dr. Kenneth VanBik of San José State University for serving as the driving force in my desire to pursue an education and career in linguistics. His encouragement was always incessant and steadfast, and his approach to teaching will always be my golden standard. An equal serving of gratitude goes to my other committee members, Drs. Soteria Svorou and Julia Swan, for their valuable contributions to this thesis. I would also like to thank my good friend, California State Parks Docent Bill Rhoades, whose constant, refreshing support for my academic endeavors has been much appreciated. Finally, I would like to thank my mother, Susan Agee, whose continued unconditional support for my studies has not been without appreciation. vi TABLE OF CONTENTS LIST OF TABLES.

Historical Glottometry, introduced by Kalyan & François (2018), is a wave-based quantitative approach to language subgrouping used to calculate the overall strength of a linguistic subgroup using metrics that capture the contributions of linguistic innovations of various scopes to language diversification, in consideration of the reality of their distributions. This approach primarily achieves this by acknowledging the contribution of postsplit areal diffusion to language diversification, which has traditionally been overlooked in cladistic (tree-based) models. In this paper, the development of the Germanic language family, from the breakup of Proto-Germanic to the latest period of the early attested daughter languages (namely, Old English, Old Frisian, Gothic, Old High German, Old Low Franconian, Old Norse, and Old Saxon) is accounted for using Historical Glottometry. It is shown that this approach succeeds in accounting for several smaller, nontraditional subgroups of Germanic by accommodating the linguistic evidence unproblematically where a cladistic approach would fail.