> The precise nature of the relationship has not been worked out yet
-- > we have no consistent theory of PIE "root extensions".
That's one reason I thought it would be nice instead to find a way
to nip off 'extensions' - to form new words subtractively so to speak;
it saves you the trouble to come up with a meaning for the extensions
(since then there aren't any). This could be done by eg. 2,3sg aorist
erasing not just the ending but the root-final consonants too, the
result of which (with lengthened vowel!) users could see as a new root.
Ex.: *bhudh- *bhu:-
On the other hand, I have suspicion that the 'extension' *-g- that
makes up the difference between *yeu- and *yeug- is some kind of
phonetic excretion from the vowel.
Torsten