This dissertation investigates the expression of the indirect evidential subdomain in two languages in contact, i.e. the northern variety of Central Aymara and the variety of Spanish spoken in La Paz (Bolivia). For this aim, the study uses first-hand data collected in La Paz and El Alto (Bolivia) during 2014 and 2015. Data was elicited through: the “Family Problems Picture” task (San Roque et al. 2012), formulated by the members of the Max Planck Institute for Psycholinguistics and created specifically for the activation of cognitive categories such as evidentiality and mirativity; the “Pear Story” designed for Wallace Chafe, professor at the University of California, to collect narrative texts that show how humans perceive, elaborate and verbalize experience; and, finally, personal narratives, traditional narratives and interviews. Thirty-three recordings (12h 48’) of 48 Spanish-Aymara bilingual speakers (17 males, age range: 18-64) were fully transcribed and annotated. The resulting corpus consists of 33 transcriptions of which 14 are in Aymara (c. 19 154 words), whereas 19 are in Spanish (c. 46 245 words). The dissertation is built around four research questions. First, the dissertation shows the functions of the forms identified in the data in both languages. The study identifies for each form both evidential and non-evidential functions. Indirect evidential functions are systematically analyzed and classified by combining Willett’s (1988) and Aikhnvald’s (2004) classifications. The analysis shows evidential functions of forms that have not been previously studied as such, i.e. digamos and diciendo in Spanish and sañani and sapxi in Aymara, but it also reveals unnoticed evidential functions for previously described forms. Second, the dissertation provides a clear view of the relationship between the evidential and the epistemic modal domain involved in the use of the forms identified. Two types of correlation are found. Both languages, indeed, show forms that only point out the way in which speakers acquired information and forms where the two domains overlap. Third, the dissertation investigates speakers’ epistemic stance, in terms of commitment, towards information involved in the use of the evidential forms identified. The study shows that the forms which convey merely evidential information express mainly a medium-high commitment degree, whereas the forms in which the distinction between the evidential and the epistemic modal domain is blurred indicate a low degree of commitment. Forth, the dissertation sheds light on the relationship between the expressions of the indirect evidential subdomain in the two languages. The study proposes a quantitative and qualitative analysis of the evidential types and subtypes in both languages. The results show a high degree of convergence between the two languages, suggesting also situations of influence of one language on the other.