Nuance gives developers free access (but not for high volume) - See http://www.masshightech.com/stories/2011/09/26/daily13-Nuance-tweaks-mobile-dev-program-with-free-access-to-Dragon.html or http://dragonmobile.nuancemobiledeveloper.com/public/index.php?task=home
Nuance services are typically offered commercially and require up front fees and transaction fees. The interesting news above is that they now make low volume use of their services available to developers for free. So, for development, testing, and demonstration you can probably use the free Nuance services. However, unlike the Google services that come free in Android, if your app has thousands of users you will likely have to pay for Nuance services.
