A vocal jazz style that consists of improvised nonsense syllables sung to an an improvised melody, usually over an instrumental accompaniment. This is similar to vocalese where voices replace jazz instruments with the addition of words.
There are some who believe that scat singing had its origins in the music of West Africa. The percussion patterns may have been changed to vocal lines by assigning syllables to the standard rhythms. It is more probable that scat singing was an outgrowth of jazz singers in the United States imitating the sounds of jazz instruments. It was documented in early New Orleans jazz and early blues recordings.
Louis Armstrong took scat singing to new heights in the 1920's and many of his early scat solos were as innovative as his trumpet solos. Cab Calloway moved the art form into the more complex bop idiom in the 1930's, and in the 1940's and 50's, Ella Fitzgerald was known for her imitation of jazz instruments. Scat singers are like any jazz musician and each creates a unique sound that consists of syllables, rhythm patterns and other vocal devices. Ward Swingle (the Swingle Singers) applied scat singing to classical music in the 1960's and created a new audience for bop scat singing. Many innovations in scat singing has been employed since the mid-20th century which include musical and non-musical vocal sounds such as mumbling, laughing, sobbing, screaming, growling, humming, and yodeling.