Yodeling (also yodelling or jodeling) is a form of singing which involves repeated changes of pitch during a single note. The singer quickly switches 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 (and originally Austro-Bavarian) word jodeln, meaning "to utter the syllable jo" (pronounced "yo" in English). This vocal technique is used in many cultures worldwide.