The Aramaic proclitic *dalet*, widely used in historical Hebrew texts, serves two distinct grammatical functions: as a subordinating conjunction and as a possessive preposition. Because these functions are orthographically identical and no annotated resources exist for this task, large-scale computational analysis of their usage has previously been infeasible. In this paper we introduce a new BERT model for historical Hebrew in which all prefixes are segmented and encoded as independent tokens. This representation allows the model to evaluate proclitics directly and provides a probe-based unsupervised method for determining the grammatical role of the *dalet* clitic using masked language modeling predictions. We evaluate the approach on a manually annotated dataset drawn from historical Hebrew literature spanning multiple regions and historical periods, achieving over an average F1 score of over 0.89. Applying the method to a corpus of more than 300 million words of historical Hebrew texts, we conduct large-scale stylistic analyses of the choice between the Aramaic *dalet* and available Hebrew alternatives. The results reveal geographic and diachronic trends and identify distinct stylistic clusters within the corpus. The prefix-segmented model and annotated dataset are released for unrestricted use.

The corpus of post-Rabbinic historical Hebrew is a foundational corpus of Jewish heritage, containing over a billion words of legal, hermeneutical, and philosophic texts (and more). However, because the linguistic norms of the corpus diverge so often from that of modern Hebrew, the corpus cannot be computationally analyzed with existing Hebrew parsers. In order to fill this lacuna, we present the first Universal Dependencies corpus of post-Rabbinic historical Hebrew. The corpus comprises over 11,800 words, and we are pleased to release it to the community.