This text discusses the Critical Collaborative Research known in Brazil as PCCol – Pesquisa Crítica de Colaboração - which is a practical-theoretical approach used in the development of investigations that focus on understanding and often challenging knowledge production and actions so as to promote de organization of decolonial-and-inclusive schools. Standing on Marxian, Vygotskian and Freirean underpinnings, the text was written from the recordings of two classes delivered by the authors in a Graduate Course called Critical Research Methodologies, with participation of some guest professors, such as Maria Cecilia Camargo Magalhães, who also authors this paper. The text is organized from the speeches of the authors on two occasions in which they collaboratively delivered lessons about PCCol, as well as the questions and interventions from the other course participants. The writing procedure interweaves speeches, treated as data, and their analyses, treated as the actual discussion of some of the concepts that base the Research Methodology itself, and that include relational and transformational agency, the Freirean notion of data production from the South rather than the North, professional practice that is personal and collectively responsive, but more specifically, we will discuss the role played by language for the implementation of collaborative interactions, as well as how this type of language is organized.