Making computers available everywhere, to everyone, is going to mean making speech recognition available for every language. The Microsoft Universal Phonetic Set (MUPS) project starts from the idea that we can collect the data in only one language, and perform a slight, language-specific, mathematical transformation to make it correct for the others. It will initially concentrate on getting and sharing data for English, French and Spanish. The goal in the long run is to share senones, the very small units that make up a single phoneme, building models of how human mouth, tongue, and lips form sounds.
When everyday applications of SR technology are concerned, entering text quickly and easily is one of its main strengths. Two broad categories, discrete and continuos speech recognition, are used in different scenarios. In discrete dictation, the system stores a predefined vocabulary of recognizable words, and the user must pause for a few milliseconds between words. This limitation disappears in continuos dictation products, resulting in a more natural interaction. Modern packages can now distinguish between a command to the PC and continuos dictation, making separate dictation and command modes obsolete. Limited processing power - typical for the embedded environments - is now one of the rare reasons to use a discrete speech recognition. Compared to the average speaking speed of 180 words per minute, input rates of up to 130 words per minute achieved by fully trained SR systems will clearly boost productivity in a text based environments. "Fully trained" means that you'll have to spend some time on a process called enrolling that includes reading a couple of basic sentences, sufficient for the software to create a basic user profile. Failing to do that will result in a frustratingly poor performance and limited productivity. And remember that even the best SR system won't work properly without a tiny piece of hardware. Background noise will greatly reduce accuracy rate so special noise cancellation headsets are recommended for all recognition packages.
More info on speech recognition technology, including a high-level explanation of basic concepts can be found in ZDNet Speech Recognition Special. But speech recognition technology isn't restricted only to PCs. An excellent introductory article from Speech Technology Magazine titled "Speech-enabled Appliances" describes SR and TTS technology in home and office appliances.