Until recently, the Phoenician reflex of *ay did not seem to warrant much attention. Van den Branden, Segert, and Friedrich & Röllig were content to give the reflex as ë and supply a few examples2. It is only in the last decade that scholars have begun to suggest that the monophthongization of *ay in Phoenician (or, rather, its ancestor, Old Canaanite) two outcomes: ē and P.
Steiner, Richard C. “On the Monophthongization of *ay to ī in Phoenician and Northern Hebrew and the Preservation of Archaic/Dialectal Forms in the Masoretic Vocalization,” _Orientalia_, vol. 76, no. 1 [=Festschrift for Maria Giulia Amadasi Guzzo] (2007): 73-83
*This is constructed from limited available data and may be imprecise.