Having legends on the keycaps isn't really a big deal, it's about forcing yourself to use more than two fingers. This will be incredibly frustrating at first, but it typically doesn't last for long.
http://data.typeracer.com/pit/profile?user=precariousgrayI had a splint on my left index finger for a few weeks (thanks, burgeoning arthritis!) and this was really annoying for a while. After a week or so I was able to type without that finger at 80-90% of my normal speed. Bad habits can be hard to break, but fortunately this one is relatively easy.
This is
not an absolute, since there's always that element of improvisation depending on where my fingers happen to be, but those are mostly the fingers I use to strike certain keys.
Start slow. It may help you to simply take a few sentences or a list of words and practice them over and over, always using this same set of practice material, that way you can tell how quickly you're improving.
In the end, just accept that you're going to have to put forth a little effort, but you will definitely be able to speed up over time; it's not impossible like some things in life. Good luck!