There are several previous studies on Vietnamese terms of address and reference. Included among them are several Vietnamese grammar books. However, most such studies consist of a collage of the various forms of address in this language, including their denotative meanings and general usage (Cooke, 1968; Thompson, 1987; Nguyễn Đình-Hòa, 1997). Others discuss the pragmatic aspects of the usage of particular terms of address, for example, the social meanings of personal pronouns (Nguyễn Phú Phong, 2002; Nguyễn Văn Thành, 2003), and kinship terms (Spencer, 1945; Benedict, 1947; Nguyễn Tài Cẩn, 1975; Luong, 1984; Lê Biên, 1999; Cao Xuân Hạo, 2003; Szymańska-Matusiewicz, 2014). Also, there are studies that illustrate the complexity of the usages of these terms to convey politeness and appraisal (Vũ Mai Yên Trần, 2011; Phuc Thien Le, 2013; Ngo & Unsworth, 2011). However, apart from those denotative and social meanings that Vietnamese terms of address convey, it is also their affective meanings, or the emotional messages transferred through switches of these terms during conversations that constitute the complexity and also the unpredictability in Vietnamese address practice. This thesis builds on and extends this previous body of literature by providing empirical evidence through systematic data collection and analysis, including conversation analysis of telenovelas, content analysis of movie subtitles, EFL students‘ translation tasks, and professional translation works. With a special focus on switches of address terms during speech events among Vietnamese speakers, this study examines the situation-regulated affective meanings of Vietnamese terms of address, which are not their intrinsic property. It argues that it is important to study how these terms are employed in different contexts for different purposes, especially for the purpose of expressing one's emotions. Multiple sources of data were used. These include a total of 147 episodes of television series, equal to approximately 110 hours, of two Vietnamese telenovelas; a review of 5 professional translation works (English to Vietnamese and Vietnamese to English); 49 translation papers performed by third-year students who majored in English (Translation and Interpretation) from the Faculty of Foreign Languages at the University of Dalat (Vietnam); a questionnaire for teachers of translation and interpretation courses that sought to better understand EFL students' translation outcomes; and face-to-face interviews with two professional translators (one in Sydney and another in Hanoi). The major findings of the study indicate that interactants' choices of address terms demonstrate their different states of attitude or emotion, which strengthens the argument that Vietnamese address terms have affective meanings, most of which are not an innate property, but can be revealed and interpreted in combination with other address terms and the situational context. The research results confirm and illustrate the general view among scholars that unlike those of many other languages, Vietnamese address terms pose major translational challenges particularly as a consequence of such factors as the relationships between the interlocutors, their relative age, and social, cultural, and emotional status. Overall, the originality and significance of this thesis lie in its innovative interdisciplinary approach that combines three branches of applied linguistics, namely pragmatics, translation studies and EFL teaching. These sub-fields of applied linguistics are usually studied in isolation of each other, thus overlooking the insights to be gained from a more integrated approach where the three are treated as complementary. The thesis innovatively uses insights from these three areas of research to contribute new empirical and theoretical ideas on how terms of address implicate emotions of speakers. The study draws on Vietnamese terms of address to illustrate the particular point about linkages between linguistic usages and the expression of emotions, and also the difficulties in solving the gaps or discrepancies between Vietnamese and a language such as English during the translation process.