Does tvátpitārah = ευπατωρ? Accents, amphikinetics, and compounds in Sanskrit, Greek, and Indo-European

A standard comparison in Indo-European linguistics equates Vedic tvátpitārah ‘having you as father’ and Ancient Greek compounds in -πατωρ, e.g., ευπατωρ ‘having a good father, lineage’. Many scholars describe this equation as resulting from “Internal Derivation”: the second-member of the compound would exhibit amphikinetic inflection, internally derived from a noun with hysterokinetic inflection. This paper reassesses the philological evidence for the long-vowel forms of Vedic -pitār-. Because the long-vowel forms are confined to one Vedic school (Taittirīyans), it is argued that the short-vowel forms such as -pitar- reflect the inherited Indic vowel length in these compounds. Following this reassessment, I question to what extent the second-members of possessive compounds (e.g., Gk. -πατωρ) reflect an “amphikinetic” paradigm. I argue that the forms are “amphikinetic” only to the extent that they show an o-grade suffix in Greek, and that defining such second-members as amphikinetic both overgenerates (predicts unattested forms) and undergenerates (fails to predict attested accents).