The Baby-Sitters Club #16: Jessi’s Secret Language Book by Ann M. Martin. Jessi learns American Sign Language when she begins sitting Matt, a deaf child. Then the Baby-Sitters Club comes up with a great idea: why not teach all their regular charges sign language? Soon everyone is learning to sign, and Matt makes some new friends.
Jessi knows a secret language! She learned it from Matt Braddock, the BSC’s newest charge. Matt’s been deaf since birth, and he uses sign language to speak. Since Jessi is Matt’s baby-sitter, she’s been using sign language, too.
Soon all the kids in Stoneybrook want to learn to sign . . . which keeps the Baby-sitters busy. Jessi’s the busiest of all: she working on another secret just for Matt. Will she be able to keep the secret and pull off her special event?