Gary Morgenthaler, a partner at the venture capital firm Morgenthaler Ventures in Menlo Park, California, was the first VC investor in Siri and was a Siri board member until Apple acquired it, as well as an investor and board member of Nuance Communications, the voice recognition software company whose technology also is used by Siri. Both companies were spun out of the research institute SRI International.talked with Bloomberg about Apple Inc.’s Siri speech-recognition software.

Dow Jones recently had a conversation with Morgenthaler about why voice is the new user interface and what he wants to invest in next.

Q. Why is Siri such a big deal?
A. First there was the mouse, then gestural and now this. Conversational interface is the third advancement in user interface. Theres a lot of excitement around this because people see its a whole new way of interacting with computers thats easier and more efficientits a more human way of connecting with computers.
Gary Morgenthaler says that within two to three years, Siri will respond as fast as a human, except where network service is poor. People are realizing that once you try this, there’s no going back. Within two to three years, you can expect Siri to respond as fast as a human, except where network service is poor.

Q. How do we push forward from here? How does Siri become the default UI platform?
A. Today, Siri is limited to 15 use cases: texting, email, calendars, notes, reminders, music, directions, web search, etc. These use cases are mostly Apple internal that make the iPhone 4S more productive and easier to use. What’s left to be done is to open it up to the 200,000 developers. The real revolution will be when Apple opens it up and developers begin building applications on it.

Q. So what will you be investing in?
A. Perfunctory speech applications are dead. It seems a given that you will be able to talk with your Macintosh and your iPad in the future using Siri. But why not Apple TV? Why shouldn’t you be able to request entertainment services at home from your couch and have Siri intermediate and provide those services for you?
More broadly, it’s easy to imagine myriad uses for Siri in your car and for other devices in your home. Why shouldn’t you be able to speak to them in ordinary language to elicit information, services and transactions? Now that Siri exists, these extensions of the technology seem inevitable.

Morgenthaler talks with Emily Chang and Cory Johnson on Bloomberg Television’s “Bloomberg West.”

[Thanks to MacDailyNews Reader "Fred Mertz" for the heads up.]