During her time at JHU, she twice served as directeur d'Etudes associé at the Ecole des Hautes Etudes en Sciences Sociales.
She has supervised the completion of seventeen PhDs by her graduate students at JHU and taught both graduate- and undergraduate-level courses on medieval history and historiography.
Her best known theoretical work is "History, Historicism and the Social Logic of the Text in the Middle Ages," published in the academic journal, Speculum, in 1990.
In this article, Spiegel addresses the challenges that the linguistic turn poses to the historical profession and offers the "social logic of the text" as an interpretive lens that locates written sources within the social, political and economic currents that shaped the discourse of the moment while simultaneously foregrounding the active nature of the author’s work as he seeks to reconstitute and reshape reality as he writes.
[5] Her 1993 monograph, Romancing the Past: The Rise of Vernacular Prose Historiography in Thirteenth-Century France sought to demonstrate the utility of such an approach to historical sources.