In pluralistic nation such as ours, the function of government should be to foster and support the similarities that unite us, rather than institutionalize the differences that divide us. ProEnglish (http://www.proenglish.org/main/gen-info.htm) They tell me, 'Go back to Mexico, don't speak Spanish' Juan, Latino student at Junction High School Introduction The purpose of this article is to describe the prevalent linguistic ideology of certain members of dominant Euro-American group. (1) This linguistic ideology was encountered during an approximate eight month critical ethnographic action research project. In response to reported experiences of prejudice and racial discrimination by transnational newcomer students, seven teacher inquirers (2) engaged in an intercultural peace curricula development project that was facilitated by the author during the 2004-2005 school years at U.S Midwestern High School. Though the original dissertation research study design was not focused on mapping the prevalent linguistic ideology at Junction High School, attitudes about non-English language use quickly became central to our peacebuilding efforts. (3) Data presented here relays these attitudes as well as cultural assimilationist orientations exhibited by some students, teachers and administrators who were members of the dominant Euro-American population. The attitudes and linguistic normative monitoring of members of this dominant social group at Junction High School (4) created non-peaceful (5) school and classroom environment for newcomer students whose first languages included: Spanish; Japanese; Mandarin; and Arabic. Related research further examines everyday understandings of peace and non-peace at Junction High School (Brantmeier, 2007b) and also gives more in-depth description of the process of building intercultural empathy (Brantmeier, 2007a). In this article theoretical discussion of the terms linguistic ideology and cultural assimilation foregrounds description of the action research methodology employed in the dissertation study. Findings related to non-peaceful attitudes and behaviors, more specifically data related to attitudes about language and cultural assimilationist orientations, are then presented. A discussion follows that connects themes in the data analysis to wider cultural debates concerning language use and identity in the United States. Finally, call is made for further research that maps how dominant linguistic ideologies are enacted and countered. Theoretical Discussion: Linguistic Ideology and Cultural Assimilation Working conceptions are needed for the terms ideology and linguistic ideology. Apple (2004) describes functional understanding of ideology as a form of false consciousness which distorts one's perceptions of social reality and serves the interests of the dominant class in society (Apple 2004: 18-19). Understood in this light, an ideology is social construction that serves the interests of situated group of people within society; unequal power relationships are maintained through the propagation of an ideology. Apple focuses on class relations in the previous definition. The term linguistic ideology here is linked to broader focus on power and place, to race, to class, to regional dialects, to the language spoken, and to related status and power differentials in linguistically diverse environments. Rumsey (1990) describes linguistic ideology in terms of everyday understandings of language practices, or notions about the nature of language in the world (Rumsey 1990: 346). This commonsense understanding of right or correct language use can have consequences for those who lie outside the dominant linguistic norms. Thus, linguistic ideology can be understood here as dominant, everyday attitudes and practices concerning language use that serve to reinforce power and status differentials among members of population within situated social contexts. …