From Wikipedia:
Behold his "trading fours" (call-and-answer) with bandmate Dave Lambert here:
Example: Duke Ellington's "Cottontail" w/FAMOUS Tenor solo by Ben Webster
It's a 'verbatim" vocal solo, IOW, Jon assigned a lyric/syllable to EVERY NOTE Ben Wester played. His solo starts at 0:27, continues at 1:40. Brilliant:
Interview starts at 2:19, but (assum'g you are enjoying this ) do stick around for the few tunes they perform afterward:
For himself, #jonhendricks sang the Coltrane part.
He gave #AlJarreau the Miles part, and Bobby -the Bill Evans (piano) part.
Behold Jon vocalese-ing John Coltrane's dynamic original solo, here
"Clouds of Grey have Silver Linings when they're Reversed"
-from L,H,R's "Cloudburst"