S.B.
If you think he is chewing out of frustration from lack of communication, you could try teaching him sign language. Kids can pick it up quickly, even if they can't speak. And it will give him a sense of control. My son is 14 months & not talking yet, but he can communicate. He can sign: up, down, hungry, more, thank you, please. I am currently working on teaching him: help, book, drink. They suggest not to teach more than 3 at a time. Since he is older than my son, he should pick them up faster. There are also many more signs you can teach. I feel these signs are really good at getting you through most of the day. If you google "baby signs" a bunch of websites with free info & videos of the signs come up.
I know nothing about the chewing issue, but if you want to communicate with your son, signs are really wonderful.