Oral transmission of Sacred Harp music

The reason why Sacred Harp includes practices not notated in the music (that is, in the various published editions of The Sacred Harp) is that the printed music is not the only way that the music is transmitted among singers and across time—there is an oral channel as well. Many Sacred Harp participants can be described as “traditional” singers. They learned Sacred Harp by being taken to singings as children, and usually are the children of traditional singers of the previous generation. The parents, in turn, also learned the tradition as children.[1] Thus there is often a chain of direct transmission dating back to (or even before) the original appearance (1844) of The Sacred Harp. This chain has evidently developed and transmitted a number of singing practices distinct from what is printed in the book. As Sacred Harp scholar Warren Steel states, “traditional singers use the printed book in learning songs, and refer to it while singing, but the notes in the book are not interpreted literally, but according to a performance practice and style that is learned through oral tradition and varies among different regions and families.”

Source: How Sacred Harp music is sung – Wikipedia