The present study problematizes the role of foreign language teachers in the use of teaching materials available in their school context, based on a proposal for analysis and supplementation of an English language textbook. Is is based on contemporary theorizations about critical perspectives in language education (DUBOC, 2012, PENNYCOOK, 2001, 2006, PERSONAL, URZEDA-FREITAS, 2012, SCHEYERL, 2012, AUTHOR 1, 2015, SIQUEIRA, 2010, among others). The proposal of this study arose from the actions of a project developed under the Pro-Licenciatura program of a public university in the Midwest of Brazil. One of the objectives of the project was to produce and adapt supplementary teaching material for a beginner-level English-speaking class at the institution's Language Center, which serves the internal and external community free of charge. Thus, in this documentary qualitative research, we share part of the mentioned project, presenting the analysis of one of the chapters of the textbook adopted by that institution, based on the three worldviews discussed by Leffa (2017): the revealed, the covert and the possible worlds. The analysis points out that it is possible to adapt and elaborate teaching material based on critical perspectives for groups of basic levels, even in the face of challenging contexts and with limited resources. We conclude that the study and the expansion of teaching materials based on the three worldviews discussed by Leffa (2017) require analysis, research, reflection, critique, agency and coauthoring/co-creation in a continuous, interpretive and, above all, not prescriptive process.