I have physically held my son's and daughter's hands when they started doing this and said quietly "Chew and swallow". Or if that didn't work, I've given them only the food on their plate that I feel comfortable with them putting in their mouth. Choking is a huge fear for me and I don't mess around with it. My son is 4 and has had this impulse under control for over a year, but my daughter is almost two and will do this same thing sometimes. I think it's just a developmental thing that I've seen mentioned many many times.
We also had an issue with too big of bites with one of our children. We played the "counting" game to see if he could chew a certain number of times...made it a game and it worked great! (slowed our eating pace down too) Good luck.