This paper investigates the relationship between speech perception and linguistic experience in Kaqchikel, a Guatemalan Mayan language. Our empirical focus is the perception of plain, ejective, and implosive stops. Drawing on an AX discrimination task, a corpus of spoken Kaqchikel, and a text corpus, we make two claims. First, we argue that speech perception is mediated by phonemic representations which include acoustic detail drawn from prior phonetic experience, as in Exemplar Theory. Second, segmental distributions also condition speech perception: The perceptual distinctiveness of a pair of phonemes is affected by their functional load and relative contextual predictability. These top-down factors influence phoneme discrimination even at relatively fast response times. We take this result as evidence that distributional factors like functional load may affect speech perception by shaping perceptual tuning during linguistic development. This study replicates and extends some key findings in speech perception in the context of a language (Kaqchikel) which is structurally and sociolinguistically different from the majority languages (like English) which have served as the basis of most work in the speech perception literature. At the practical level, our research illustrates methods for conducting corpus-based laboratory phonology with lesser-studied and under-resourced languages.