The present paper aims to reflect on the development of research in LL, to analyze its role and aims, and in particular to offer a critical discussion of the methods and tools used to collect and interpret data. This analysis intends to highlight that LL studies have expanded since the flagship study by Landry and Bourhis (1997). The objects, methods, and tools of analysis in LL have changed in order to satisfy different research goals, to describe specific aspects of LL, and to interpret and understand the public space with different and often interdisciplinary approaches, i.e. semiotic, sociological, political, geographical, economic. Starting from the authors' research on immigrant languages in Italy and from the existing literature, the objective here is to describe how both methodologies and objects of analysis have developed over the years.