Today, virtually all speakers of Mapudungun (formerly Araucanian), an endangered language of Chile and Argentina, are bilingual in Spanish. As a result, the firmness of native speaker intuitions – especially regarding perceptually complex issues such as word-stress – has been called into question (cf. de Lacy, 2014). Even though native intuitions are unavoidable in the investigation of stress position, efforts can be made in order to clarify what the actual source of the intuitions are, and how consistent and ‘native' they remain given the language’s asymmetrical contact conditions. In this article, the use of non-native speaker intuitions is proposed as a valid means for assessing the position of stress in Mapudungun, and evaluating whether it represents the unchanged, ‘native’ pattern. The alternative, of course, is that the patterns that present variability simply results form overlap of the bilingual speakers’ phonological modules, hence displaying a contact-induced innovation. A forced decision perception task is reported on, showing that native and non-native perception of Mapudungun stress converge across speakers of six separate first languages, thus giving greater reliability to native judgements. The relative difference in the perception of Mapudungun stress given by Spanish monolinguals and Mapudungun-Spanish bilinguals is also taken to support the diachronic maintenance of the endangered language’s stress system.