This thesis describes the form and function of verb stem alternations (VSAs) in Vaiphei, a Kuki-Chin (KC) language belonging to the larger Tibeto-Burman branch of the Sino-Tibetan language family. In the existing literature on Vaiphei and Kuki-Chin verb stem alternations, there is no treatment of the form and function of Vaiphei verb stem alternations and how they may be used in classifying Vaiphei in the broader Northern Kuki-Chin language family. I document the form and function of Vaiphei verb stem alternations, showing how these compare to other Northern Kuki-Chin languages and where to classify Vaiphei in Northern Kuki-Chin. Participants were selected based on their knowledge of Vaiphei and English and their access to the internet. These subjects participated by completing questionnaires translating English sentences into Vaiphei. Data was collected using Voice over Internet Protocol (VoIP) platforms such as Skype and WhatsApp. Vaiphei VSAs showed a strong similarity to other Northern KC languages, with forms identical to VSAs in Sizang. Functions of VSAs were largely similar to other Northern KC languages, including valency changes, subordination, nominalizations, and subject focus. Grammaticalization of the verb piak "to give" into a benefactive morpheme, however, shows an innovation in the Vaiphei VSA system.