It is not easy to build an intelligent software, the cooperation on all the levels of the speech processing needs to be tight. For example, you should not only recognize the input but also understand it and, more importantly, respond to it. You need to give your software an ability to understand the current situation, correct the results and respond intelligently. A great piece of software to assist you with that has been recently release.
OpenDial is a Java-based software toolkit that can be used to develop robust and adaptive dialogue systems for various domains. Dialogue understanding, management and generation models are expressed in OpenDial through probabilistic rules encoded in a simple XML format.
You can find more information about the toolkit on the project website:
http://opendial.googlecode.com
The current release contains a completely refactored code base, a large set of unit tests and a full-fledged graphical interface. You can also find on the website practical examples of dialogue domains and a step-by-step documentation on how to use the toolkit.
Try it!