| Answer | Crossword Clue |
|---|---|
| signing | the use of sign language |
| signings | SIGNING, the use of sign language |
| KOKO | Gorilla trained to use sign language |
| KOKO | Gorilla famously taught to use sign language |
| dactylology | the study of sign language |
| dactylologies | DACTYLOLOGY, the study of sign language |
| EPEE | French priest who pioneered the development of sign language |
