"Happy Birthday to You" is a song which is sung to celebrate the anniversary of a person's birth. According to the Guinness Book of World Records, "Happy Birthday to You" is the most popular song in the English language, followed by "For He's a Jolly Good Fellow" and "Auld Lang Syne". The song has been translated into many languages, though it is often sung with the English lyrics even in countries where English is not a primary language. It's also the most frequently sung song in the United States[citation needed].

The melody of "Happy Birthday to You" was written by American sisters Patty Hill and Mildred Hill in 1893 when they were school teachers in Louisville, Kentucky. The verse was originally intended as a classroom greeting entitled "Good Morning to All". The version as we know it was copyrighted in 1935 by the Summy Company as an arrangement by Preston Ware Orem, and is scheduled to expire in 2030. This was the first copyrighted version to include the lyrics. The company holding the copyright was purchased by Warner Chappell in 1990 for $15 million dollars, with the value of "Happy Birthday" estimated at $5 million. [1] While the current copyright status of the song is unclear, Warner claims that unauthorized public performances of the song are technically illegal unless royalties are paid to them. It is not completely certain who wrote the lyrics to "Happy Birthday to You"

source from:
http://en.wikipedia.org/wiki/Happy_Birthday_to_You#.22Happy_Birthday_to_You.22

Dear sis-Kathy:
Happy birthday to you ! Here is my greetings -------->

Happy Birthday To You ,Happy birthday to you,Happy birthday to Kathy, Happy birthday to you!!!
:)