Mark, I appreciate your response. I tend to quibble about any word or abbreviation which is overused in crosswords: ALE, ALP, AGUA, ERA, IRA, IRE, ISLE, NNE, SSW, SRTA, UKE, LEI, ALOHA, ARENA, OGLE, ORCA, OREO, et al. As for CACTI and OCTOPI, those plurals are now in common usage, which is why they're included in dictionaries. To me, CACTUSES and OCTOPUSES are the plurals. (Do any Americans use OCTOPODES?) Many dictionaries also say, based on popular usage, that "temp-ə-chər" is now the preferred pronunciation of "temperature" and "kumf-tər-bəl" is the preferred pronunciation of "comfortable." If "comfortable" is pronounced "kumf-tər-bəl," then why is "comfort" never pronounced "kumf-tər"? I am a language purist -- I will always say "com-fort-ə-bəl" and "tem-pər-ə-ture" and pronounce "harass" with the accent on the first syllable.
I'm still, however, trying to figure out why we never say "I aren't" but yet we ask "Aren't I?" The word should be "amn't." It looks strange and it's seldom used -- but it's grammatically correct.