In his research, he has examined, in addition to the Indo-European verb, such issues as the origin of the Balto-Slavic pitch accent and the internal reconstruction of the earliest stages of the Proto-Indo-European language.
In addition to the Indo-European verb, he has treated such issues as the origin of the Balto-Slavic pitch accent, Germanic and Celtic nominal morphology, and the internal reconstruction of the earliest stages of the Proto-Indo-European language.
[1] His research has contributed to integrating Hittite and Tocharian verbal morphology into the reconstruction of the Indo-European verbal system, though he emphasizes that “the post-h2e-conjugation model of the PIE verb is (…) in many respects extremely conservative”[2] and “The novelty of the ‘new’ system is entirely at the formal level.”[2] His novel reconstruction of the Proto-Indo-European middle in the context of the *h2e-conjugation theory as proposed in Hittite and the Indo-European verb and subsequent articles has been adopted by several textbooks[3][4] and has been generally well-received.
The Proto-Indo-European sigmatic aorist is traditionally reconstructed with Narten-ablaut of the root (ē/e), an invariant stem-forming suffix *-s-, and the athematic secondary endings.
[3] However, the corresponding active preterit categories in Hittite and Tocharian show an *-s- only in the third person singular, as well as evidence of an unexpected o-grade of the root throughout the paradigm.
Jasanoff argues that this situation reflects an archaism and that the classical s-aorist emerged from an older *h2e-conjugation aorist with o-grade of the root, whose 3sg.
The proposed original paradigm thus looked as follows: After Anatolian and Tocharian split off, the third singular active form became the starting point for the development of the “classical” s-aorist found in Indo-Iranian, Greek, Latin, etc.