The origin of the Latin -iēs/-ia inflection

This paper traces the possible origin of the Latin -iēs/-ia inflection. The main facts as attested in Latin are presented alongside the main hypotheses postulated so far on the origin of this type of inflection. The theories are reviewed and, consequently, a new solution is put forward which takes into account some of the previous attempts and the Sabellic material. The origin of this type of inflection is traced back to the Proto-Italic stage where the continuants of the Proto-Indo-European devī́, vkī́ḥ and *-iā- paradigms intermixed with each other. Afterwards, the devī́ and vkī́ḥ paradigms merged into a single one with a new instrumental-ablative in *-iēd created on the model of the consonant-stems, followed by an analogical creation of the nominative in -iēs on the model of *diēd :: *diēs.