I know it is very hard to eat after tongue surgery and radiation, I was fortunate not to need chemo. You must be persistent and try to exercise your tongue. Have they given you any physical therapy to do. Also be aware that radiation is the gift that keeps on giving. I had my cancer 6 years ago and am having voice and swallowing issues now and having to take more physical therapy regarding this. Wish I had started sooner after my initial surgery and treatment. I never had to have a feeding tube but was limited to liquids and very soft food for about 8 months and gradually worked up to other kinds. It was a good two years before I was able to eat most foods comfortably. Hang in there and keep the faith. I'll keep you in my prayers.
VC