This indicates healthy neural development. Twitching will be most pronounced for the first few months of the puppy's life and slowly diminish there after. There are many adult dogs that continue some twitching. Expect muffled woofs and snuffling noises, too. Your puppy hiccups.
Many puppies hiccup.
The only thing to do is wait for them to pass. Don't worry about it, they will out grow it. If you watch a litter of puppies playing, you will notice that they spend much of their time biting and grabbing each other with their mouths. This is normal puppy behavior. When you take a puppy from the litter and into your home, the puppy will play bite and mouth you.