Go to your library and check out "Baby Signs" by Linda Acredolo and Susan Goodwyn. It's a book on modified sign language for babies/toddlers. (Some of the signs are American Sign Language but others are not.) I started using it around 6-8 months with both of my kids. When my son was little we would have whole conversations with him signing and me saying the words he was signing. You could tell he was thrilled that I understood him! He would look out the window and make the tree sign and I would say, "Yes, there's the tree." He would make the sign for squirrel and I looked and sure enough, there was a squirrel in the tree so I said, "Oh, there is a squirrel in the tree!" He grinned from ear to ear! There are lots of signs in the book. Once my son could say the word, he quit using the sign. Studies show that children who use signs first have a great vocabulary later. My son definitely does for his age, (he's 4 now.) If your son can communicate with you better, he will be less frustrated, not to mention most signs are hand signals so that will get his fingers out of his mouth! Since he's not a baby, he will learn the signs quickly, (my daughter is 10 mos. and understands a lot of signs that I make but doesn't use many just yet.) Good luck! The book is awesome, (I bought it on Amazon and have seen it in Target.)