[wideawake]

Most of this is quite right but in one respect:

all neuter plurals in -a were originally feminine collective nouns, hence the use of the neuter plural in Greek with verbs in the singular

you may be overstating your case.

That's one theory as to why this is so common in Greek (and also in medieval Italian, Vulgar Latin and Provencal), but it's atheory.

[Rte66]

I agree. A little broad-brush on the “all -a groups” being feminine. Don’t want to think more about it right now, tho, lol!

[lentulusgracchus]

you may be overstating your case.

That's one theory as to why this is so common in Greek (and also in medieval Italian, Vulgar Latin and Provencal), but it's atheory.

I was citing Leonard Palmer and Carl Buck. Grant you that their scholarship is older, but the subject hasn't changed much..... perhaps more recent scholars like Bonnie Urciuoli no longer subscribe to this "theory" (which wasn't presented as a theory at the time it was propounded), but that's my best sources.