Having fallen off my bike recently and broken my collarbone means that I can't type with both hands, for a consultant this is a poor place to be. Now that I'm on the mend I decided to buy dictation software, as it may be another 3 to 4 weeks before I can type while again.
There is pretty much only one option for dictation software on the Mac. Dragon Dictate is a retail only package, because it comes with a dedicated headset, this is a Plantronics 610 with an approximately 2 m long cable. It plugs into a specific USB adapter and the Dragon dictation software listens to this. There is a wireless version for about £100 more. I bought the wired version of Dragon Dictate from Amazon for £130.
I got the software yesterday, it takes about 10 minutes to install. The headset is quite comfortable and the setup takes about another five to ten minutes. since then I've used it to write about half a dozen e-mails including words like peripatetic, pneumothorax and phrases like King's Cross. It is pretty accurate and certainly faster than one-handed typing. It does require a slightly different way of thinking as Dragon dictation works best with flowing sentences, it makes many more mistakes if you give it halting fragments of text. It works by matching word frequency and sound analysis. There is an inherent statistical bias towards Americanised speech, but it's quite straightforward to edit this. One annoying bug is its habit of adding space before every word while editing. So if you are not careful you can end up with double spaces between words betraying your edits. I'm hoping they will fix this in a subsequent revision.
Reading on various support forums for Dragon Dictate it seems that having a recent i.e. less than two-year-old Mac running 10.6 is pretty essential. Having 4 or 8 gig of memory installed helps a lot as well. The ability to dictate directly into MarsEdit or Mail is a real help. I can see myself using this quite a lot even when I have recovered, as despite having written a book my typing speed has never been that quick. I'm aware that this won't work very well in a shared office, but for using at home it is fine.
I'll update this review, as I use and train the application more. It is possible to both train Dragon dictation in terms of the vocabulary you use by giving it documents you have written and train it to your voice by reading sample documents they provide. I think a few hours spent doing this will improve the accuracy a lot. At the minute it varies a lot from stretches of near-perfect, when I give it 10 to 20 words at a time to getting one in 10 words wrong if I give it halting speech. Because of the statistical nature of its matching it often substitutes phrases rather than getting individual words wrong. So you develop a habit of reading what it is just typed for you, which is a slightly odd style of writing. Though on the whole it is a good and enjoyable experience.