The absolutive voice is a fact of life for Guatemalan children who speak the Mayan language K'iche' and one that enters their verbal lexicon fairly early. Data suggest that by the time the children are 3-year-olds they have encountered several instances of verbs that alternate between active and absolutive forms, which may supply the evidence needed to formulate a general rule. Lack of errors in children's language production indicates that the children were extremely sensitive to the formal properties of the absolutive antipassive. They do not simply assume that every verb they meet in a transitive context is transitive. Yet, to acquire the absolutive antipassive, K'iche' children face three major hurdles. The first is learning that root transitive verbs can have intransitive forms, i.e., the absolutive alternation. The second is learning which verbs do not undergo the absolutive alternation. And the third is learning which intransitive verbs are root or derived. The last two problems cannot be solved from positive evidence alone. Nor are conservative acquisition procedures likely to be the explanation, given the propensity of children learning English to generalize beyond verb forms they have already heard. While this report does not explain how K'iche' children formulate a properly restricted rule for the absolutive antipassive, it does show that the absolutive raises learnability problems of the same level as the English dative or causative. (RH)