R.S.V.P. comes from the French phrase, 'répondez, s'il vous plaît,' which means 'please reply.' According to western etiquette, you should reply promptly if you receive a formal invitation.
Switching letters is called spoonerism. For example, saying jag of Flapan, instead of flag of Japan.
More Language Facts
One thousand contains the letter A, but none of the words from one to nine hundred ninety-nine has an A.
Skepticisms is the longest word that alternates hands when typing.