Re: [tied] "u" versus "a"

>>>> Compare _salsus_ "salty; witty" vs. _insulsus_ "unsalted; boring".
>>>>It's the outcome of a series
> > >> of regular sound changes
> > Other examples of exactly the same series of changes are:
> > resultum (resilio, cf. salio)
> And insultum (insilio, cf. salio)
> > adultus (adolesco, cf. alo)
> And sepultum (cf. sepelio)

There are two different phonological processes here. One is the change of
described above:
-VlC > -ulC in medial syllables
the other is what happens to original syllabic l:
*-l.C > -ulC
(Both, of course, involve the same reduction.)

If they are worth distinguishing, then adultus and sepultum are, I think,
the second, not the first. They would never have had an -a- vowel, whereas
salsum/insulsum clearly did. There are others as well, though I can't think
of any more with -a- vocalism in the present tense.

Peter