I have grown up with the view that I was right handed. It now appears to me that it is a false view. I could have been left handed also but the way I interacted with feedback from society led to my right handedness. I think I am not right handed as much as right tongued.
It is hard to teach an old dog new tricks because of the multitude of habitual responses. However I believe that I could become 'left tongued or at least bi-tongued if I keep at it. The feel of the left tongue gets stronger and stronger easier to access and I perceive that I can use it in speech at will..
Still cannot move it across the midline without switching back to my normal right tongue mode. I have a sense it plays in with the dominant eye thingy. The difficulty may lie in the right giving up the position of dominance as much as the left acquiring it.