1. A system, comprising a computer, the computer comprising a processor and a memory, wherein the computer is configured to: register each of a plurality of application grammars, and further wherein registering an application grammar includes determining whether a command in the application grammar conflicts with a command in another grammar registered in the computer; receive input including at least one word; determine that the input is specified as a command in a plurality of the grammars, each of the grammars being associated with a respective instance of one application in a plurality of instances of the application each currently running on one of a plurality of devices; select one of the currently-running instances of the application to which to apply the command according a specified status of the selected instance of the application; and provide the command to the selected one of the applications.