My question is about a song. The Guiness Book of World Record says this as the most popular song in the English language. The melody of this song was written by American sisters Patty Hill and Mildred Hill in 1893 when they were school teachers in Louisville. This song was published in 1924 and it copyright does not expire till 2030. Can you readers name the song?
Update : For the curious, the answer is "Happy Birthday to you"