This study presents a description of conservative forms of the spoken Spanish in the Nahuelbuta area (North-west of the Araucanian region). These forms are related to the cultural aspects of colonial tradition. These circumstances are nowadays maintained by a Hispanic-Creole society ("sociedad hispano-criolla") of the frontier type that has displaced the native population towards adjacent territories. The mentioned Hispanic-Creole society has lived to the present much disconnected from the urban culture up to the present.En este artículo se describe el carácter conservador del castellano hablado en Nahuelbuta (noroeste de la Araucanía), aspecto ligado a formas de cultura de raíz colonial, mantenidas por una sociedad hispano-criolla de tipo fronterizo que, históricamente, desplazó a la población nativa hacia territorios vecinos y que ha permanecido bastante desvinculada de las formas culturales urbanas.