Yodeling

Yodeling (also jodeling or yodelling) is a form of singing which involves repeated and rapid changes of pitch between the low-pitch chest register (or "chest voice") and the high-pitch head register or falsetto. The English word yodel is derived from the German word jodeln, meaning "to utter the syllable jo" (pronounced "yo"). This vocal technique is used in many cultures worldwide. Recent scientific research concerning yodeling and non-Western cultures suggests that music and speech may have evolved from a common prosodic precursor.

the distinctive, ululating yell of the character Tarzan as portrayed by actor Johnny Weissmuller