As a host and also speeker, Selena Gomez gave a speech about “Trust Yourself” became a main point at the annual charity event "WE DAY" in California, is the research object for this study, which analyzed the textual and interpersonal functions included in the speech by using MAK Halliday theory, SFL framework. The researcher has identified themes and modalities in the spoken text and has employed data collection techniques, supplementing the object analysis with documentation to obtain a more thorough outcome. In this study, Selena Gomez's speech, is examined for its themes and modalities, its textual and interpersonal functions explained, and its global and pedagogical implications discussed. This study employed a descriptive qualitative methodology by applying CDA approach, according to the researcher. The data were recorded using the instruments of this research—the blog and the YouTube channel of English Speeches Channel—by selecting 16 viewers and recording their comments in order to obtain a deeper analysis. The findings indicate that the most often occurring themes using Thematic analysis in Selena Gomez's speech were Textual (87 times), Topical (67 times), Interpersonal (18 times), and Multiple theme (93 times). In terms of modality analysis, modulation was most frequently utilized (discovered 21 times), followed by negativity (15 times) and modalization (4 times). The study's instructional implications included helping students comprehend the textual and interpersonal meaning through the use of speech texts, which gave researchers a better understanding of advanced discourse analysis subject at the university, in order for the students to comprehend the primary idea of the clause and evaluate the meaning conveyed in the spoken text.