This whole Talk Like A Pirate Day madness started back in the 1990s as a joke between two - and I’m sad to admit - Oregonians. To make a lame story short, these two guys were playing racquetball and started speaking like pirates. They enjoyed themselves so much they decided to make it an annual experience, a festival of sorts. That was back in 1995 and for seven years the day was celebrated by only a handful of people. It was during the 1992 gathering that famed humor columnist Dave Berry showed up to participate. An ensuing column helped spread word of this useless, mindless jamboree. (source: NewWest)
related:
TalkLikeAPirate.com
Wikipedia
