As a turn-design strategy, repeating another has been described for English as a fairly restricted way of constructing a response, which, through re-saying what another speaker just said, is exploitable for claiming epistemic primacy, and thus avoided when a second speaker has no direct experience. Conversations in Mesoamerican languages present a challenge to the generality of this claim. This paper examines the epistemics of dialogic repetition in video-recordings of conversations in three Indigenous languages of Mexico: Tzeltal and Yucatec Maya, both spoken in southeastern Mexico, and Lachixío Zapotec, spoken in Oaxaca. We develop a typology of repetition in different sequential environments. We show that while the functions of repeats in Mesoamerica overlap with the range of repeat functions described for English, there is an additional epistemic environment in the Mesoamerican routine of repeating for affirmation: a responding speaker can repeat to affirm something introduced by another speaker of which s/he has no prior knowledge. We argue that, while dialogic repetition is a universally available turn-design strategy that makes epistemics potentially relevant, cross-cultural comparison reveals that cultural preferences intervene such that, in Mesoamerican conversations, repetition co-constructs knowledge as collective process over which no individual participant has final authority or ownership.