Question

The technique of improvising nonsense syllables vocally was called _____ singing.

Answer 1

Answer: scat singing :)
explanation: In vocal jazz, scat singing is vocal improvisation with wordless vocables, nonsense syllables or without words at all. In scat singing, the singer improvises melodies and rhythms using the voice as an instrument rather than a speaking medium.

Answer 2

The answer is scat singing