I used Dragon Dictate and it was terrific until I began having the earliest of breathing problems. In fact, it was trying to use Dragon Dictate that tipped me to the fact that my breathing was a little impaired. Speaking requires a lot of lung power. Dragon is good about learning small changes in the enunciation of words but not so helpful when you get short of breath. It is patient and will allow you to dictate in short sentence fragments though.
I recommend you also begin using onscreen keyboards to save energy typing. Click-N-Type is free and excellent for short bits of typing. You can also program macros with it so you can type stored info such as addresses, phone and zip numbers, and any sentences, phrases, etc. you need to use often.
Dasher also free, is the real genius in onscreen typing though. Instead of a hunt and peck keyboard, you just "drive” your mouse or eye gaze toward the next letter effortlessly. It allows rapid typing and the ability to type all your thoughts without derailing your train of thought. I use it constantly! I do find it easier to get my thoughts typed out and then use Click-N-Type to correct any typos or rearrange sentences or paragraphs.
Between these two programs I can type with ease!
