The term 'Alpine Trill' is a type of yodeling, which is a form of singing that originated in the Alps. Yodeling is characterized by alternating between the chest and head voice, creating a trilling sound. The term 'YODEL' is derived from the German word 'jodeln, ' which means to sing with rapid changes in pitch. Alpine Trill is a specific type of yodeling that is used in traditional Swiss and Austrian folk music.