Abstract
One of the defining features of the Old Armenian (OArm.) verb is its binary stem system: almost every verb has two stems, present and aorist, from which all forms may be derived. The aorist stems are traditionally divided into two types, strong (unsuffixed) and weak (suffixed), the latter characterized by a suffix ending in -cʿ-.
All scholars agree that the latter is an innovation; its exact origin has been much discussed, but consensus takes it to be from PIE *-sk̑e/o- in iterative past usage, parallel to but independent of Ionic Greek ἔχεσκε 'had, held', φιλέεσκε 'loved', δόσκε 'gave', etc. The only aorists that must be taken as direct reflexes of PIE imperfects are precisely beri (eber) 'carried' and aci (ac) 'led', which not coincidentally go back to the praesentia tantum *bʰer- and *h2eg̑-.
If Armenian inherited suppletive aorist stems beside these presents, they must have been replaced early on with the continuants of PIE impf. *bʰer-e-, *h2eg̑-e-, which were later ousted from their original function by the innovative berei (berēr), acei (acēr). As a category, the Old Armenian strong aorist must be regarded as a lineal descendant of the PIE root aorist, with thematized endings (except for edi, etow, eki), generalization of either zero-grade or full-grade root, and in some cases adjustment to the present stem.
The last step resulted in numerous verbs with identical present and aorist stems, which were then secondarily differentiated by means of the productive present stem-forming suffix -an-, leaving only the exceptional set of berem, acem, nstim, and hanem.