addenda/s...alumni

[sagehen]

>>Benjamin Barrett writes:
>A question I've had for some time is why there are so many alumni
>associations. Is there are reason why they aren't alumnus associations?
>Or are irregular plurals normally used that way?
>
 Is it irregular? Relying on my memory of high school Latin sixty yrs
ago.......
I suppose you could have alumnorum -- an assoc. of graduates.  Or perhaps
the *alumni* assoc. is *a* graduate's assoc. (that is one to which a grad
is entitled: genitive sing. not nom plural).
I guess the use of  the term *alumnus/i * is for the purpose of being
inclusive, that is, entitling all former students whether  they achieved
degrees or not.
Rereading your question, it occurs to me that you may mean the irregularity
of using a plural adjectivally......?
A. Murie