Mindanao is a large island in the Philippines, and has many different languages and dialects.
Here's why there isn't one single vocal form:
* Linguistic Diversity: Mindanao has a diverse population with numerous indigenous groups, each speaking their own language or dialect.
* Major Languages: Some of the major languages spoken include Cebuano, Tausug, Maranao, Maguindanao, and Hiligaynon.
* Filipino: Filipino, the national language of the Philippines, is also widely spoken on Mindanao.
Therefore, it's impossible to pinpoint one "vocal form" for the entire island.
It's important to be respectful of the linguistic diversity of Mindanao.