I have been trying to talk with the left tongue. Not that successful in maintaining it for any length on time (prolly because of the lack of self discipline. I am probably the least organized most undisciplined person I know. ) Anyway I was responding to my wife using the left tongue and she said "Your sounding like your mouth is paralyzed." I agreed because that is how my left tongue feels. Like it does not have much nuance in it's ability to find the proper shape to create the sounds I want.
Does not prove anything about the left tongue but I am happy that what my wife said verifies my internal sensation.
update- Eating with my wife and she noted that I was not moving my lips. When I tried getting my left side of my lips to be incorporated she said you are only using the left side of your lips. It was what I was trying to do. More important that this is not really about the tongue, lips, throat or face but about communication using these structures. It more and more feels that the positive feedback that I got lead to enhancement of my communication skills on the right and to neglect of the left.