How does drone polyphony work in traditional Polynesian music?

In traditional Polynesian music, drone polyphony is an indigenous vocal technique widely practiced across most Polynesian groups, with the notable exceptions of the Maori of New Zealand and the Hawaiians.1

This form of polyphony functions through a two-part structure:
* The Melody: One part performs the primary vocal line, which is typically rooted in chant or heightened speech.1
* The Drone: A second part accompanies the melody by following it rhythmically while consistently repeating a single, fundamental tone.1

Authorities on the subject agree that this use of a drone is a precontact element of Polynesian music, distinct from other polyphonic forms—such as imitational counterpoint—that are believed to have emerged following European influence.1