Second Language (L2) teacher education serves as a pivotal site for examining language ideologies that shape teacher candidates' conceptualization and enactments of L2 pedagogy. Informed by the theory of language ideologies (Kroskrity, 2004, 2010) and the concept of language socialization (Ochs & Schieffelin, 1984), this dissertation research investigates naturally occurring interactions between teacher educators and teacher candidates to reveal language ideologies circulating within the L2 teacher preparation program at a Midwestern state university. Drawing upon an ethnographic perspective (Green & Bloome, 2004), this study examines the nature of classroom negotiation and contestation of language ideologies within the program by focusing on three critical issues. First, what language ideologies circulate through the engagement between teacher educators and teacher candidates? Second, how are these language ideologies constructed and negotiated? Third, how do these language ideologies mediate teacher candidates' conceptualizations of L2 pedagogy? The findings demonstrate that native-speaker ideologies and bi/multilingual language ideologies circulating within the program represent the complexity, multiplicity, and contradiction of language ideologies. Native-speaker ideologies are manifested in teacher candidates' beliefs that interaction with a native speaker is a preferred and valuable condition to facilitate L2 acquisition and development. These ideologies also underpin their construction of the notion of linguistic authenticity. Bi/multilingual language ideologies are reflected in teacher candidates' conceptions of content-and-language instruction as a bi/multilingual learning space for bi/multilingual students by promoting the employment of students' primary language to support the comprehension of academic content and language and legitimize their bi/multilingual identities. These ideologies are also manifested in teacher candidates' constructs of language assessment, pedagogical approaches to language variation, and corrective feedback practices. The findings highlight that as agents of socialization teacher educators play a key role in promoting or challenging language ideologies. In a similar vein, the materials selected as the resources of learning for teacher candidates also function as socialization instruments that influence the formation or transformation of teacher candidates' language ideological orientations. Through the understanding that classroom discursive interactions, teacher educators, and course materials play a key role in shaping and reshaping teacher candidates' language ideologies, this study offers L2 teacher preparation programs insights and information that could improve efforts toward promoting pedagogical approaches that allow teacher candidates to critically problematize the hegemonic language ideologies that do not value language multiplicity and diversity. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]