A system and method are disclosed for voice command coordination between instances of the same application running on multiple devices. The devices could be any that process voice commands, such as smartphones, tablets, smartwatches, laptops or IoT devices. The system coordinates the devices by broadcasting short communicates using humaninaudible sonic frequencies. In the first step of the method, the user gives a voice command, which is received in a number of devices that interpret the command. Each device determines a relevancy score of the command and then broadcasts the score as short communicates using inaudible sonic frequencies that are received by the other devices. Thereafter, each device receives short communicates with relevancy...