Urban migration triggers new processes of ethnic identity among mapuche people in Chile. Given this, we propose a new approach towards the conditions that rules the use and transmission of mapudungun among urban speakers in the context of a general linguistic shift process. The empirical base of the investigation was obtained in semi-structured interviews with urban speakers of mapudungun in Santiago, Temuco and Concepcion, between 2006 and 2007. The representations about autobiographic episodes make possible to follow an analytical path that focuses on the social spaces identified for the use of mapudungun, and the new experiences of acquisition and re-use of the language. We state that through the speakers' testimony it is possible to reveal processes of socio-cultural change and ethnic resistance that seeks to counterbalance the diglossic model that rules the use options of mapudungun in the Chilean urban setting.