I think have been playing more with left sublingual extrinsic musculature of the tongues than the intrinsic musculature as say this gal. I used to feel the extrinsic musculature of both sides as one undifferentiated mass with what I believe was right side dominance. The left side was just tight with no sense of independence. I am coming more and more to the feel the whole left side of my head was not used independently but more of a stabilization platform for the rights side role in communication/speech. There should be no reason I feel such a strong connection with my left sublingual musculature with the left posterior muscular structures of the neck but as I get 'play' in the left sublingual musculature the whole of the left side of my head is involved. There is both a positive and a negative sense that presents itself. A good feeling of play in muscles that never did it before and a sense of discomfort as the same muscles are fighting 55 plus years of one track habitual use.
However I think it is far more the function of communication than any individual muscles that dominate the relationship of both the left and right side.