Here are some tips on how to get started using speech recognition software for dictating emails, papers, etc. If you have RSI or just don't like typing, the good news is that the technology has come a long way in the last few years and works quite well these days.
Yes, your PC has some speech recognition built into it. But the very best stuff is Dragon NaturallySpeaking. Recently a version for the Mac has shipped, which is supposed to use the same internals & so should perform equally well. For years the mac version had weird bugs, but I think those are ironed out now.
As of March 2012 the latest version is 11.5, though I think version 10 is nearly indistinguishable in terms of performance so if you can pick up a used copy that's a good way to save some $. There are several "editions" with various features. I recommend the Preferred version, which has a couple of useful features not available in the entry-level Home verison. If you absolutely must have the very best there is the Professional version, but I think it's wasted money.
"Doesn't it come with a microphone? Can't I use the same built-in microphone I use for Skype?" Yes and yes, but if you want dictation to work really well then you will want to get yourself a high quality microphone. I would say that having a quality microphone is more important than having the latest software. The one in the box is neither accurate nor comfortable. A good microphone isn't cheap, but it will make the difference between success and frustration.
There three main types of microphones:
Of course I haven't tried every microphone out there, so you may find something that works better for you. What I would encourage is buying from a microphone store like emicrophones.com as they really know the products and can help you find the best solution for your needs. Ask for Marty.
For years, the knock on dictation software was that you had to spend an hour training it to your voice. As of a couple of versions ago, Dragon eliminated this requirement so that you can just use it right out of the box. DON'T DO THIS! Pleeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeease take a few minutes to go through the training process. Even better, do an extended training session of 20m or so. You'll be very glad you did!
The other aspect of training is to have it not just learn your voice (as above) but also to learn your writing style. For example, if you are used to writing academic prose Dragon doesn't know that ex ante. What is very helpful is to have Dragon read some of your papers - don't worry, you don't have to read the documents to it out loud; you just point it to a folder or a collection of Word or text docs you want it to read. it will learn the writing style and also come back with a list of words it hasn't heard before. Also, I would take a minute to speak the words it doesn't know, including author names. It'll work much better.
The final thing to do is to make corrections as you use it. so, if it misses a word, go back and higlight that phrase (not just the word) and correct it. It helps to highlight the phrase because Dragon uses n-gram language models that depend on knowing which words tend to follow each other. So, if you said "unresolved endogeneity" but Dragon thinks you said "unresolved endangerment", don't just highlight "endangerment" and fix it; highlight the whole phrase and fix it. That way, Dragon will learn that those two words are likely to appear together.
That's it! Good luck and feel free to get in contact if you have questions. Susan Athey also has a page on using dictation for equations in particular.