The connectivity inherent in an Internet of Things design gives a boost to voice technology in that it allows the heavy lifting of natural language understanding to occur in the cloud rather than in the device. This means that voice technology is available to a wider variety of devices and applications than it would have been if it were part of a self-contained design. I wrote about one such offering in my blog Natural Language Voice Control Comes to the Internet of Things at IoT World.
Still, the technology of voice recognition is only part of the puzzle. Developers still need to structure the system to mitigate potential problems with things like background noise and separating commands from conversation.