addenda/s...alumni

[Benjamin J Barrett]

I noticed my real estate agent using the pair addenda/addendas
yesterday. He did it more than once. The escrow agent he was talking
with used addendum, but I didn't hear her use a plural form.

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?

Benjamin Barrett
Baking the World a Better Place (with ice cream)
www.hiroki.us