This stunning effect is made with battery powered flash lights, bike lamps, sparklers, cold cathode lights, anything bright. Here are some basics:
To get the best results you need a tripod. The exposure should be around 10-30 sec. or longer if needed. Stay in front of the camera and do your writing.
To not overexpose set the camera to about ISO 100, and close your aperture as much as possible. If there is still too much light you might have to use a neutral density filter.
If you stack enough similar pictures, you get something like this: