It's the Shepard tone effect running in the background of the actual notes, which produce a mild illusion that they're ascending when they're not, but nevertheless they're moving up and then down in pitches so it's not a brilliant example. I think the author is a little confused in this short essay about a few things. His "talking piano" effect is just standard vocoding, which has made me think this is all fairly new to him and he's not an expert.
THIS is a talking piano: https://youtu.be/muCPjK4nGY4