Faldo is right. I regularly insert words into the "private dictionary" function on this old coal-fired steam-driven computer of mine. One of my recurrent nightmares is that something will happen to this machine which will cause that file to be lost and I will have to rebuild a "private dictionary" from scratch. So I occasionally find the file (it is way down there in a hidden part of the hard drive) and copy it to a disk as a sort of insurance policy against disaster.