There's a demo song on the Oktalyzer disk with vocals.
The lyrics:
"This is the Amiga with 8 voices"
If anyone has a soundtracker mod called "Spasserland" (it's a rendition of the danish national anthem done with "spaz voices") I'd be very interested in hearing that again.
It was done in the late 80's by the musician from Plasma Force (famous for "Bar Brian" - another mod with vocals) who is now a drummer in C64 band "Press Play On Tape".