grammar

I know the fact that I actually care about this makes me an asshole, but:

Masculine: singular= alumnus & plural = alumni
Feminine: singluar = alumna & plural = alumnae

I actually don't care if you just use "alum" and "alums" because whatever, we're speaking English, not Latin, and the language changes over time.

That being said, I do care if you say "alumn" because if you're going to butcher the language, it should at the very least be in the service of making it more pronounceable.
I also care if you decide "alumna" is plural. Because that's dumb. I guess if the singluar was "alumnum" you'd be on to something, but it's not.