>>>Can anyone tell me why it is that Greek neuter o-stem plurals end in
>>> <-a> and not <-e:>,
>>I'm not sure what you mean here.
>The <e:> I'm referring to is the hypothetical classical Greek reflex of an
>ending *-eh2 which has been >postulated for the o-stem neuter plurals, ...
Thanks - I see what your question is now.
I don't have a definitive answer (of course!) but only ideas.
(a) have you considered the force of analogy? We know that Latin and Greek
borrowed the nom. plurals of 1st and 2nd declension animate nouns from the
pronoun stems, so alterations to inherited declensions were certainly
possible. Perhaps there was analogical force to have all neuters in -a? On
consonant stems, and -i stems and -u stems, (and the 3rd declension
neuter -s stems nouns) this would have been a short -a. Only in the
thematic stem would it have been different.
(b) The sequence -eh2 in Greek originally gives a long -a: (e.g. hista:mi
< *steh2). This is changed in Attic-Ionic dialects to a long -e: in most
cases, (e.g. histe:mi) but the fact that it is not changed in other dialects
suggests it is a late-ish phenomenon in the PIE to Greek process. There is
plenty of time for some -a: to change to short -a if there are reasons to do
so.
Peter