Among the many thousands of analogue sound recordings preserved at the Bibliothèque Nationale de France are 228 unpublished wax cylinder recordings that once belonged to the Institution Nationale des Sourds-Muets de Paris (now known as the Institut National de Jeunes Sourds de Paris). Recently digitised and descriptively catalogued by the BNF, these recordings attest to the extraordinary array of activities that took place in the Institution’s Laboratoire de la Parole over the first few decades of the twentieth century on the initiative of its first director, Hector Marichelle (1862–1929). Based on the co-authors’ ongoing research related to these recordings, this article takes an initial step towards contextualising the collection as a whole. It describes the current state of the collection and its cataloguing system, and lays out what is known about when, how, and why the recordings were initially made. Taking selected cylinders as case-studies, it discusses some of the practical and methodological challenges the co-authors have encountered in the course of their research, in particular as they have attempted to create text-based transcriptions of the recordings. This article thus aims to contribute to the intertwined histories of experimental phonetics and deaf pedagogy in early twentieth-century Europe, as well as to larger interdisciplinary conversations about how sensitive sonic heritage has become the stuff of scholarly study.