Abstract
Besides lexicons, I-Lan variety is distinguished from Common Taiwanese for the special sound /uinn/. The /uinn/ sound is descendted from Zhanzhou dialect, so this thesis examines the history of migration and language background of I-Lan. Since the sound change from /uinn/ to /ng/ in I-Lan variety results from the influence of Common Taiwanese, it is quite instructive to introduce language contact and diglossia. In addition, the change is processed with lexicons, which means different words or phrases have various speed of change, so attempts should be made to discuss lexical diffusion and bidirectional diffusion. Also, individual difference of various sound changes is owing to social factors like age, sex, or social network.This thesis contains six chapters. In chapter 2, the history and language background of /uinn/ and /ng/ in I-Lan variety and the factors that influence it will be introduced. In chapter 3, the theory of lexical diffusion, bidirectional diffusion, language contact, diglossia, and social factors are applied to explain my observation. In chapter 4, the main attention will be focused on the investigation and analysis of I-Lan variety nowadays. In chapter 5, the topics on lexical diffusion, possible reasons of change from /uinn/ to /ng/, and future of I-Lan variety will further be discussed. Chapter 6 is the concluding chapter.