Thesis (PhD)--Macquarie University, Faculty of Human Sciences, Department of Linguistics, 2009. / Bibliography: p. 210-223. / General introduction -- A multimodal analysis of the 2006 Mexican presidential campaign billboards -- Study 2: Discourses of obligation and prohibition within an institutional setting -- Study 3: Gatekeeping practices at the LEMO: a multimodal analysis -- General conculsions. / This is a thesis composed of three studies linked by a common critical multimodal approach to the analysis of the data. Fairclough's (1992, 1995) three-dimensional framework was drawn on in order to explore the social practice, discursive practice and text dimensions of the discourses in question. The first two studies focus on printed texts in Mexican Spanish, whereas the third study addresses spoken interaction in English with occasional code switching to Spanish. -- Study 1: A Multimodal Analysis of the 2006 Mexican Presidential Campaign Billboards - This is a joint study (with my colleague Michael Witten and approved by my supervisor and the Department of Linguistics at Macquarie) which analyzes the political discourse of the multimodal and multisemiotic texts that the three major political parties involved in the 2006 Mexican presidential elections produced and extensively distributed through the medium of public billboards. We investigate how these parties express their particular ideologies, construct and convey social identities and relationships, and construct relations of power between themselves and the readers/viewers of these texts, through the medium of billboards. As indicated in the preamble, the methodological framework addresses these issues drawing on Fairclough's (1992, 1995) three-dimensional model of analysis while employing a variety of qualitative techniques, tools, and approaches. -- Study 2: Discourses of obligation and prohibition within an institutional setting - Following the theme of multimodal critical discourse analysis, this study examines the institutionalized discourses of obligation and prohibition at the Library of the Language Faculty (LEMO)*of a public university in Mexico. Six different texts pertaining to various genres ranging from a protocol to notices were examined. Multiple qualitative methodologies and tools such as those drawn from ethnography, critical discourse analysis, and systemic functional linguistics are utilized in the analysis of the data. Power relations between the institution and the library users are examined as well as the conditions of text production and reception, the latter through an ethnographic component. An emphasis is placed on the linguistic text. -- Study 3: Gatekeeping practices at the LEMO - This study investigates one of the gatekeeping practices at the Language Faculty of a public university in Mexico (see above). The particular practice concerned consists of the professional examinations (vivas) that students have to take in order to obtain their degrees of 'Licenciatura en Lenguas Modernas' (BEd in Modern Languages) in the English Teaching section of the university. This study focuses on the professional discourse(s) utilized by both candidates and examiners by means of analyzing the texts of four recorded professional examinations. This study chiefly draws on Goffman's (1959) dramaturgical concepts of 'frontstage' and 'backstage', where the analysis of the frontstage work addresses the Question-and-Answer section of the examinations, and the analysis of the backstage work addresses the subsequent deliberations among the examiners concerning the performance of the candidates. Multiple qualitative methodologies and tools are again drawn upon, such as ethnographic analysis, interactional sociolinguistics and critical discourse analysis. (* Facultad de Lenguas) / Mode of access: World Wide Web. / xii, 233 p. : ill. (some col.)