What song, written by Mildred and Patty Hill, is considered the most commonly sung song in the English language?

This simple tune, recognized by Guinness World Records as the most recognized song in the English language, was originally a classroom greeting. Sisters Mildred and Patty Hill developed the song in the late 19th century for Patty's kindergarten class in Kentucky. The original lyrics were "Good Morning to All," and it was published in an 1893 songbook for children. The simple and easy-to-sing melody was designed to be welcoming for young students.

The transformation into a birthday anthem is a bit of a mystery, but it's believed that the birthday-themed lyrics were adapted to the melody sometime in the early 20th century. The combination of the familiar tune with celebratory birthday lyrics first appeared in print in 1912. The song's popularity grew, and it was used in the first singing telegram by Western Union in the 1930s.

For many years, the song was under a copyright that generated significant royalties, but a 2015 court ruling declared the copyright invalid, placing the song in the public domain. This means it is now free for everyone to sing and enjoy publicly without paying a fee. The song has been translated into at least 18 languages, solidifying its status as a global phenomenon sung at birthday celebrations everywhere.