Like drones and simple harmonic intervals, parallel harmonies are common across many cultures around the globe. While not every culture handles parallel harmonic motion in identical ways, we can look to the music of sub-Saharan Africa as a case study in parallel harmony.
Homophonic Parallelism, a technique commonly used in gospel music and African American spirituals, is the harmonization of a melodic line through parallel motion. The resulting sound is a harmony that closely follows the contour and rhythm of the original melody and is used throughout all of Africa.
Homophonic Polyphony is the result of combining two melodies that have been harmonized with parallel intervals. This technique is typically combined with antiphonal call and response or melodic counterpoint to create a dense texture.
Here’s an example of homophonic parallelism applied to Nkosi Sikelel’ iAfrika, an 1897 hymn that became a Pan-African liberation song in the 20th century.