This article presents the outcomes of a 2-year pilot study of a teaching innovation project in an English-medium instruction course on sociolinguistics, in a languages degree at a Catalan university. Following the tenets of Critical Linguistics Education, our proposal aimed at promoting the students' development of metalinguistic awareness of linguistic diversity; particularly, of Englishization phenomena in their socialization spaces. Firstly, we detail the project, based on the students' interpretive analysis of the social meanings of a series of Linguistic Landscapes involving local and global languages that they gathered ethnographically. This required the use of two technologies of citizenship participation, employed as Foreign Language learning/teaching instruments: A geolocating map and a 2.0 web. We then analyze the students' productions, and their marks, course ratings and project-assessment reports. We show that the required disciplinary content and advanced English level were attained. Students became knowledge generators of sociolinguistics phenomena and developed an intercultural, plurilingual competence in 'localized Englishes'. We conclude that the use of Linguistic Landscaping is an effective means to develop the multilingual literacy, technoliteracy and learning-to-learn competences required by the European Council. This contributes to the design of pedagogical strategies fostering the students' commitment to an ethics of respect towards multilingualism.