Roth’s dissertation was devoted to rabbinic culture in late medieval Provence and Languedoc. Since then he has expanded his research in this field, clarifying the political, philosophical and social contexts of Jewish life in southern France. He has discovered and published texts from this period, including:

1. ‘Halakhah and Criticism in Southern France: R. David ben Saul on the Laws of Wine Made by Gentiles’, Tarbiz 83 (2015), pp. 439-463 (Hebrew)
2. ‘Fish, Customs and Philosophy: A Halakhic Debate in Fourteenth Century Provence’, Pe‘amim: Studies in Oriental Jewry 153 (2018): 43-85 (Hebrew)
3. ‘Mordechai Nathan and the Jewish Community of Avignon in the Late Fifteenth Century’, JSIJ 17 (2019) (Hebrew)
4. ‘A Halakhic Responsum by Moses Botarel’, Oqimta: Studies in Talmudic and Rabbinic Literature 5 (2019): 125-134 (Hebrew)
5. ‘Manuscript Fragments of Early Tosafot in Perpignan’, European Journal of Jewish Studies 14 (2020): 117-136
6. ‘A Collection of Rulings from Medieval Montpellier’, Kobez al Yad 27 (2021): 151-179 (Hebrew)

His book In This Land: Jewish Life and Legal Culture in Late Medieval Provence was published by the Pontifical Institute of Mediaeval Studies in 2021. As one reviewer wrote: "Anchored as it is in rabbinic texts and halakhic culture, this book demonstrates both the awareness that Provençal Jewry had (on all societal levels) of the centrality of the halakhic system to their daily lives, and the efforts that the rabbinic elite expended in enhancing the operation of the rabbinic courts and in constructing their halakhic positions along societally relevant lines. These developments were especially important in this period, when the Jews of Provence often approached Christian courts, especially in matters of civil law." (Speculum 100, 2025).