A common mistake

One of the books I've written is called Talking Your Way to the Top: Business English that Works (http://www.prometheusbooks.com). The book contains several sections on mispronunciations, confused word pairs, buzzwords, euphemisms, jargon, and other mistakes that keep business English from being as clear as it might be. We're butchering the language daily, and it makes us sound pretentious and silly at the same time. Here's one I've heard frequently, the last time from a banker, who really should know better:

Promissary. Come on, Ms. Banker, the word is promissory. Remember that this word means a promise to pay money. One o in promise + one o in money = two o's in promissory. Now, wasn't that easy?