Jazz vocal

Vocal jazz or jazz singing is an instrumental approach to the voice, where the singer can match the instruments in their stylistic approach to the lyrics, improvised or otherwise, or through scat singing; that is, the use of non-morphemic syllables to imitate the sound of instruments.

The roots of jazz music were very much vocal, with field hollers and ceremonial chants, but while the blues maintained a strong vocal tradition, with singers such as Ma Rainey and Bessie Smith heavily influencing the progress of American popular music in general, early jazz bands only featured vocalists periodically, albeit those with a more "bluesy" tone of voice; one of the first "jazz" recordings, the 1917 Original Dixieland Jass Band recordings featured Sara Martin as vocalist.

It was Louis Armstrong who established singing as a distinct art form in jazz, realising that a singer could improvise in the same manner as an instrumentalist, and along with American vocalist Adelaide Hall they established scat singing as a central pillar of the jazz vocal art.

A frequently repeated legend alleges that Louis Armstrong invented scat singing when he dropped the lyric sheet while singing on his 1926 recording of "Heebie Jeebies". This story is false and Armstrong himself made no such claim. Jazz musicians Don Redman, Cliff Edwards, and Red Nichols all recorded examples of scat earlier than Armstrong. However, the record "Heebie Jeebies" in 1926 by Armstrong and "Creole Love Call" in 1927 by Duke Ellington and Adelaide Hall subsequently introduced scat singing to a wider audience and did much to popularize the style. Armstrong was an innovative singer who while experimenting with all kinds of sound, improvised with his voice as he did on his instrument. In one famous example, Armstrong scatted a passage on "I'm A Ding Dong Daddy From Dumas" – he sings "I've done forgot the words!" in the middle of recording before taking off in scat.

...
Wikipedia