The best jazz singers use their voices much as horn players use their instruments.
Main Conclusion
Jazz consists largely of voice-like horns and horn like voices.
Intermediate Conclusion
The best jazz singers use their voices much as horn players use their instruments.
Premises
The great Billie Holiday thought of her singing voice as a horn, reshaping melody and words to increase their impact.
Conversely, jazz horn players achieve their distinctive sounds by emulating the spontaneous twists and turns of an impassioned voice.