The salt is going to start draining stuff out of places, organs, the brain, the skin, the joints, the nervous system. Watch what happens. I think for kids having trouble talking there is some kind of echo feedback system in the inner ear that prevents them from talking. There is some kind of experiment that you can do where as you are speaking your voice is played back to you it completely stops you from making sentences. The inner/middle ear would be a place that could get blocked and maybe cause this kind of a problem. They drain into the mastoids, that's the spongey bone behind the ears. That is porous and ever so slightly maleable. The salt will start pulling stuff out of the mastoids, allowing the inner ear to drain, and if I'm even remotely on to something here, you could see some improvements in language. I would get in there are massage that boney part right behind her ears, and see if it isn't somewhat protruding, somewhat dense and then regularly lightly massage it, maybe pushing down a little into her neck. and watch if that and the salt don't start to loosen that up, and everything else of course, and if Tommy doesn't start chatting you up a bit more.
http://www.dailymail.co.uk/sciencetech/article-3070065/Could-read-book-using-speech-jammer-Hilarious-video-shows-man-trying-failing-recite-Dr-Seuss-brain-tricked.html