Latin American Spanish developed in conditions of unique cultural synthesis, shaped by the interaction of European, indigenous, and African traditions. Despite extensive scholarship on lexical borrowings from indigenous languages of the Americas, the metaphor- forming role of indigenous linguistic substrates in contemporary youth slang remains largely unexamined. This article aims to identify the mechanisms through which indigenous languages and cultural archetypes generate conceptual metaphors in modern Latin American slang. The theoretical framework draws on conceptual metaphor theory supplemented by the concept of cultural metaphor variation. The empirical corpus comprises 343 regional slang units drawn from seven linguistic areas across Latin Am erica. The research employs conceptual analysis, cultural -historical reconstruction of source domains, and comparative analysis of Peninsular and Latin American Spanish. Findings demonstrate that indigenous languages — Quechua, Nahuatl, Guaraní, Aymara, K'iché Maya, and Mapuche — function not merely as lexical donors but generate independent conceptual domains. Seven regional metaphorical models rooted in pre - Columbian cultural archetypes were identified. The dominant mechanisms of influence are nature -mythological reframing, social - ethnic attribution, and syncretic overlay of pre -Columbian imagery onto European linguistic form. Conceptual metaphor, Latin American slang, linguistic substrate, Nahuatl, Quechua, Guaraní, Aymara, K’iché Maya, cognitive linguistics, cultural linguistics, metaphor variation, pre - Columbian cultures, mestizaje.