Richard on the morphophonemic status of English "a":
> It may not be a living process,
Exactly. Now when you can identify exactly _what_ stage of the
language between English and IE that "a" was ONLY due to
morphological processes and NEVER found lexically in verbs, then
let me know. Good luck in your search because such a thing is
evidently (next-to-)impossible in a language.
= gLeN