Exu:
> Perhaps like the present tense marker *-i.
Yes, phonetically it's a vowel but technically it's a consonant
because in IE *-i is zerograded *-Vy and *y is a consonant. What
one would have to look for is a true morpheme consisting only
of *e or of *o. I've already said my peace on how thematic vowels
don't have a unified function and therefore cannot be called a
morpheme so that leaves... nothing.
= gLeN