One of the most fundamental issues in the study of early New Persian texts is the identification, precise classification, and geographical mapping of dialectal features — such work is essential not only for understanding the linguistic history of Persian, but also for reconstructing patterns of cultural and linguistic interaction across Iran. The present article focuses on determining the dialectal nature of several linguistic features occurring in early New Persian texts either demonstrably composed in southern Iran or – as the analysis will suggest – very likely produced in this region. To achieve this aim, the study directly examines two important Early Judaeo-Persian texts: “The Jewish-Persian Law Report from Ahwaz” and a translation-commentary on the Book of Jeremiah. In addition, a rare verb form preserved among the Bamiyan Papers is analysed. This investigation is complemented by a comparative review of several other early texts, with the goal of establishing the dialectal status of a specific verbal construction and certain phonetic developments. Alongside the identification of these features, the paper also corrects earlier scholarly interpretations of particular words and expressions. Finally, attention is drawn to an important but often-overlooked methodological consideration that has significant implications for future research in the field of early New Persian dialectology.