15. The system of claim 11 , the operations further comprising: processing the voice input and the context to determine whether there is sufficient information to perform the action; and determining one or more missing parameters for the action when there is not sufficient information, wherein the potential contextual data comprises previously stored data specific to the user.
15. The system of claim 11 , the operations further comprising: processing the voice input and the context to determine whether there is sufficient information to perform the action; and determining one or more missing parameters for the action when there is not sufficient information, wherein the potential contextual data comprises previously stored data specific to the user. 17. The system of claim 15 , the operations further comprising: ranking the one or more missing parameters; and presenting a query to refine the voice input based on the ranking when the level of confidence is sufficiently low.