You don't have to teach the app your voice... it is backed by Google's voice recognition service, which generally works very well. When I first wrote the app 5 years ago things were a bit sketchy, but as they have improved it I find it to be very reliable lately. It works in any language, provided you do the work to translate the command files.
Yes, it can change radios - I didn't show that in the video but probably will in my next one where I want to set up for an instrument approach. I will be making more videos when I get a chance... I still have some technical issues to polish up. One thing I would like to be able to do is make the VR mirror window full-size on my desktop... I posted about this in the main discussion forum.
I have not been in contact with Dan... only 4 weeks to FlightSimCon.