altenbach -
I don't have access to the global dictionary, but I will try to find out how to add things to it.
As far as your learned items, they are stored in a cookie on your machine. To remove all of them, you can remove the cookie. My cookie is named mkoester@ni[1] so yours should follow the same pattern. If you open it, you will see a list of all the learned words which lets you know you have found the right cookie.
I'm not sure how to unlearn words one at a time or if there is a user interface that makes this possible. I will continue to investigate.
Thanks!
Molly K.
Web Support & Operations Manager
National Instruments