Pet Peeves

In addition to the aggravation of seeing the toilet seat up, one of my biggest pet peeves is the misuse of plural words. Two such examples I feel will occur rather often this year...

Alumnis. Contrary to somewhat popular belief, the plural form of alumni is not alumnis or alumni's; alumni is, in fact, already plural.

USAGE NOTE Alumnus and alumna both come from Latin and preserve Latin plurals. Alumnus is a masculine noun whose plural is alumni, and alumna is a feminine noun whose plural is alumnae. Coeducational institutions usually use alumni for graduates of both sexes. But those who object to masculine forms in such cases may prefer the phrase alumni and alumnae or the form alumnae/i, which is the choice of many women's colleges that have begun to admit men.

Source: http://www.answers.com/alumni&r=67

Freshmens. Same issue here: freshmen is already plural! I really don't know why it happens. The song made popular by The Weather Girls isn't titled, "It's Raining Mens."