As of now, not much is known about how Google will compete with Siri but a few interesting hirings and purchases made by the company point to heavily-updated voice-activated functions on the newest version of Android. According to Android and Me, Google's speech technology efforts are being led by Mike Cohen, who joined the company back in 2004. Prior to joining Google, Mike spent 10 years at the same company that launched Siri, Nuance Communication. Cohen has helped Google launch Voice Search, Voice Input and Voice Actions on Android phones, which haven't been nearly as successful as Siri but – then again – Google certainly has more experience than Apple developing voice recognition apps.
Google also acquired a company called Phonetic Arts at the end of 2010. The company works not on voice input but voice output – or improving the automated voice that talks back to you from your gadgets. Phonetic Arts was swallowed up by Google just as the company's engineers were beginning work on Ice Cream Sandwich, so we can be pretty sure that Google has been thinking a lot about how to create meaningful vocal communication between the Nexus Prime and users.
We also expect the Prime to come with facial recognition and tracking technology. Will Android's voice-recognition software track your moods? That could be cool or creepy depending on exactly how it works.
The one thing we seem to know, conclusively, is that Google is certainly working on something to one-up what has already become one of the most popular new features to land on any smartphone ever. How well Google's new voice recognition software works could be the crucial factor in distinguishing it from the iPhone 4S, but only time will tell what it will look like.