So when we swallow it seems two different forces are in play. It seems that the front pushes, and the back squeezes the airway. I believe that its this pattern that is key in facial growth. If you look at the angle of this of swallow. It seems the root of the tongue is pushing backwards and upwards, while the front of the tongue pushes forwards and downward.

This makes me think that the front of the tongue and the root work in antagonistic ways. It seems that when I stretch my tongue for example, I'm not really stretching the front, but the back root of the tongue. And when I contract the back of my tongue upwards and backwards, the tongue tie on the front of my tongue gets a stretch. I think its this stretching and contracting that forms the face, and leads to differences in facial form.

This pattern can especially be seen when a dog drinks water. If you look up a video of a dog drinking water, the dog stretches its tongue out as far as possible, and then contracts the root of the tongue as hard as possible to bring the water in.

If you think about it as well, the more mobility your tongue has, the more ability you have to reach your wisdom teeth and push food out. I think expansion of the jaw is possible with a stronger tongue as imagine the tongue pushing food towards the teeth and how much force that could potentially generate.