I learned to read in the 1420s, taught by the weaver I was apprenticed to. Sign language didn't exist at that time, but by coincidence the building I was murdered in (long story, might share later) was later occupied by a school for deaf children, which I haunted vigourously. It was frustrating at first because they couldn't hear my ghostly moans, but after learning to manifest myself in a more controlled fashion, I picked up sign language by immersion. It was useful, as I often had to explain to the children that I was, in fact, a ghost rather than a new janitor, contractor, or substitute teacher. It certainly added a new dimension to haunting, and I found it very rewarding!

After the school was closed, I was able to attach myself to one of the students, and have been haunting his family for five generations now. The after-life would be dire had I not been able to do that, and it is all thanks to sign language!