Some insights on voice interfaces from Ian Bicking:

Voice interfaces are voice interfaces. They are a way for the user to express their desire, using patterns that might be skeuomorphism of regular voice interactions, or might be specific learned behaviors. It’s not a conversation. You aren’t talking with the computer.

I’ve been speaking with Alexa for quite some time now — we like to talk about the status of the lights in the living room and which is the most suitable time for me to wake up.

Also very true:

I hate how voice interfaces force us to speak without pauses because a pause is treated as the end of the statement. Many systems use a “wakeword” or “keyword spotting” to start the interaction. What if we used keyword spotting to determine the end as well? “Please” might be a good choice. It’s like the Enter key.