Welcome to the MCF board.
I know very little about what you're asking for but I did google 'shaker exercise esophageal speech' and there were quite a few hits.
Am sure you've researched this, but if you haven't, google is your friend:Google is your friend
Oddly enough, I found a website for another board member today that might be of help:Web Whispers
Go to the Search function and enter your search criteria; for example, shaker exercise esophogeal speech
Best of luck, my friend. I wish you well.