Many years ago I purchased Learn to Speak French which was supposed to teach the user how to speak french. One of the features that I was particularly impressed by in this program, was where the user repeated words and saw their pronunciation matched graphically with that of a native speaker. You can see a screenshot of part of this process in the preceding link.
As a procrastination activity inspired by this memory during a moment of distraction, I've been searching for information on processing speech. sndpeek looks like a promising place to start, with source code and Windows binaries available for download. There's also an IBM developerworks article on identifying speakers that uses sndpeek, which is probably worth further reading.
Saturday, 27 June 2009