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Here I thought Nuance was entirely a software only voice recognition application and come to find they have 3000 transcribers working for them. Here's a link to an April 2008 press release:
http://www.nuance.com/news/pressreleases/2008/20080401_vm2txt.asp
“The Nuance Voicemail to Text Service integrates speech technology with over 3,000 Nuance transcriptionists, hosted in a Nuance-owned facility, with proven security, scalability, and reliability.”
So it looks like even the giant in the voice recognition field needs a little human help to increase accuracy.