Anna-Maria Hefele is a German overtone singer. Hefele is from Grafing near Munich. This technique of singing polyphonic overtones is also known as "throat singing," and Hefele has been practicing it since 2005. There are several styles of overtone singing found around the world. Canadian Inuit and several forms displayed in Mongolia and surrounding regions are the most recognized. Hefele's style is culturally practiced in the Siberian region of Tuva. This whistling vocal version is called sygyt.