This page has a bunch of additional details on the Pro 3 Wavetables, and instructions/links for tools to create your own wavetables and import them to Pro 3:
https://www.presetpatch.com/article/Sequential-Pro-3-Wavetables-and-EditingThe process, in short:
1. Record a short wave file with a word or phrase (best results only a few syllables)
2. Import the the audio wave file into WaveEdit or other program to create 16 keyframe / wavetable slices
3. Export the 16 slices as files and then import them to the official SequentialWaves tool to turn them into a Pro 3 wavetable format.
4. Import the .syx wavetable from SequentialWaves into your Pro 3.
5. Use an envelope mapped to Osc 3 shape to scan through the wavetable
There's a few wavetables of other vocal samples available here:
https://www.presetpatch.com/synth/sequential-pro-3 (search the filter for "wavetable")
ie: I did one that uses the famous NASA audio for "The Eagle Has Landed" (6 syllables... this is about the most you can do with still making out the words... it has a sort of robotic /lofi sound as-is)