Alexa demo — Google’s — In conversation, there are no errors.

As you can hear, Alexa asked for the full phone number including the area code but the user didn’t give out area code. In a typical voice device design such as automated systems (i.e, IVR), it’d trigger what is known as No Match error (i.e, “I’m sorry — I didn’t get that. Please tell me your…”). In this design, Alexa didn’t even acknowledge the “error” but rather recovered the user gracefully — just like you’d in real-life.