Bebop was a term used to describe the nonsense syllables used in scat singing which was a popular vocalising style around the late 20s in the US. It had originated in Ragtime music and was taken into mainstream jazz by Louis Armstrong. Many artists recorded scat music including Ella Fitzgerald and Cab Calloway. Released from the constraints of formal words, nonsense words and meaningless syllables allowed the human voice to be used as an effective instrument for vocal improvisation. Some of the nonsense words like "doo-wop”, “razzamatazz,” “skoobie-doobie-do,” “hi-de-ho” and bee-bop-a-lula,” survived to enter the common lexicon.