In his Treatise on the Astrolabe Chaucer engaged simultaneously in two kinds of translation—translating from one language to another and translating highly specialized knowledge into a form that could be more easily understood by nonspecialists. These two simultaneous translations are linked to one another using the reader persona of Chaucer’s ten-year-old son. Chaucer uses a child as the ideal audience (or reader) to communicate both aspects of his translation. This article demonstrates how Chaucer’s vocabularies, including words adopted from Arabic, allowed (...) him to use English as a language for scientific knowledge and for articulating and creating new communities of scientific readers and practitioners. To do so, Chaucer introduced the concept of experience as a necessary component of acquiring natural knowledge: using the astrolabe is as important as reading about it. I demonstrate that while he maintained the centrality of experiential knowledge to understanding nature, Chaucer also established English as a scientific language, arguing that the concept of experience and the role of the English language in scientific inquiry are linked. (shrink)